Tumours Flashcards
@# 6. A 60-year-old woman undergoing follow-up CT under the care of the oncologist develops a new expansile lytic lesion. Which of the following primary tumours usually causes an expansile lytic metastasis?
A. Cervix
B. Uterus
C. Ovary
D. Thyroid
E. Rectum
D. Thyroid
Renal cell carcinoma also causes expansile lytic metastases.
- Which of the following causes parallel spiculated (hair-onend) rather than divergent speculated (sunray) periosteal reaction?
A. Osteosarcoma
B. Ewing’s sarcoma
C. Sigmoid colon cancer metastasis
D. Hemangioma
E. Meningioma
B. Ewing’s sarcoma
Other causes include syphilis and infantile cortical hyperostosis.
- Which of the following is a cause of increased rather than decreased uptake on bone scan?
A. Cysts
B. Haemangioma
C. Leukemia
D. Spina bifida
E. Recent tooth extraction
E. Recent tooth extraction
Haemangioma and leukaemia as well as myeloma can show increased uptake as well.
- A 20-year-old man is referred for suspected malignant transformation of an osteochondroma. Which of the following is a cause for concern in an osteochondroma?
A. New lucency
B. Reduced scintigraphic activity
C. Growth plate before physeal closure
D. Asymptomatic nature
E. Cartilagenous cap > 0.5cm
A. New lucency
Concerning features for malignant transformation include new lucency, increased scintigraphic activity, growth after skeletal maturation, pain after puberty, cortical destruction and a cartilaginous cap > 1.5cm.
(Ped) 17. Which of the following is a feature of Ollier’s disease rather than Maffucci syndrome?
A. Associated with granulosa cell tumour of the ovary
B. Predilection for tubular bones, hands and feet
C. Very large enchondromas
D. Growth disturbance of long bones
E. Absence of haemangiomas
E. Absence of haemangiomas
Both are associated with juvenile granulosa cell ovarian tumours and other malignancies. The presence of multiple enchondromas with haemangiomas indicates Ollier’s disease.
- Which is the most common location for giant cell tumour?
A. Proximal tibia
B. Proximal femur
C. Distal femur
D. Proximal fibula
E. Patella
C. Distal femur
50-65% occur around the knee, but are rare in the patella.
- An osteoid osteoma is thought to be the cause of painful scoliosis in a 20-year-old man. Which of the following is the single best answer regarding osteoid osteomas?
A. The nidus appears sclerotic with surrounding lucency on CT
B. Most commonly found in long bones of the lower limbs
C. The nidus does not enhance on CT
D. Reactive sclerosis around the nidus is uncommon
E. The nidus demonstrates decreased activity on bone Scintigraphy
B. Most commonly found in long bones of the lower limbs
Although osteoid osteomas can occur in any bone, they are most common in the metadiaphyseal femur and tibia. The nidus appears lucent on radiographs, intensely active on bone scan – with surrounding well-defined luceny (double doughnut sign), isointense to muscle on T1 and variable SI on T2.
@# 24. Plain film, CT and MRI are performed for the investigation of suspected chordoma. Which is the best answer?
A. Radiographic appearances show sacral osteosclerosis
B. Coarse calcification often present with associated soft tissue
C. Areas of low attenuation within a mass on CT
D. Intermediate SI on T2
E. Arise from the spinal canal
C. Areas of low attenuation within a mass on CT
Chordoma usually appears as a low attenuation mass on CT.
- A 60-year-old man with several months’ history of back pain, worse when sitting, and with no bowel or bladder symptoms, undergoes evaluation with MRI. This shows a lobulated presacral mass, low SI on T1 with several areas of high SI within it, most likely to represent areas of calcification and haemorrhage. Which is the most probable diagnosis?
A. Chordoma
B. Chondrosarcoma
C. Myxopapillary ependymoma
D. Metastasis
E. Giant cell tumour
A. Chordoma
This is the most common primary malignant tumour of the sacrum.
Giant cell tumours are the second most common cause and are indistinguishable from chordomas on MRI.
- Which of the following indicates telangiectatic osteosarcoma (TOS) rather than an aneurismal bone cyst (ABC)?
A. Enhancing septa without nodularity on MR
B. Marked expansile remodelling of bone
C. Cortical thinning
D. Presence of osteoid matrix with septal regions on CT
E. Presence of haemorrhagic spaces
D. Presence of osteoid matrix with septal regions on CT
Thick peripheral septa with nodularity, presence of an osteoid matrix within nodular or septal regions, and aggressive growth features such as cortical destruction indicate TOS rather than ABC.
- Considering post-radiotherapy changes of soft tissue tumours on MRI:
A. Earliest radiation change is demonstrated by increased SI in marrow between 6-12 weeks
B. SI changes are due to replacement of marrow by fat
C. In most cases, complete replacement occurs in 12-14 weeks
D. Regeneration of normal marrow is common
E. Radiation field is usually poorly defined on MR
B. SI changes are due to replacement of marrow by fat
The earliest changes occur 1-6 weeks after therapy is initiated and is due to replacement of marrow by fat.
Complete replacement occurs within 6-8 weeks.
Due to high radiation doses used in soft tissue tumour treatment, regeneration of normal marrow is rare, but can occur in young patients.
The radiation field is usually well-defined.
- Considering soft tissue response to chemotherapy:
A. Neoadjuvant chemotherapy increases recurrence-free survival but not overall survival in high grade soft tissue sarcoma
B. Chemotherapy may cause a substantial increase in tumour size initially
C. Tumour size is the most accurate predictor of biologic response to tumour treatment
D. Contrast enhancement limits interpretation of intralesional necrosis
E. Intralesional haemorrhage post-chemotherapy is very rare
B. Chemotherapy may cause a substantial increase in tumour size initially
Treatment induced necrosis is a more accurate predictor of tumour response than size.
Tumour size can indeed increase initially due to intralesional haemorrhage.
The degree of necrosis is best evaluated with gadolinium enhanced T1 fat suppressed sequences.
Neoadjuvant chemotherapy increases both recurrence-free and overall survival.
- Which of the following favours chondroma rather than chondrosarcoma?
A. Size > 3cm
B. Pain
C. Age > 30
D. Location in hands and feet
E. Permeation into soft tissues
D. Location in hands and feet
Chondromas are usually < 3cm, painless and in younger patients in the peripheral skeleton.
- In a 19-year-old male with painful scoliosis, a well-defined 3cm geographic osteolytic lesion is seen in the right posterior seventh rib with slight expansion and sharp sclerotic margins. CT is performed and shows punctate calcification within the lesion and adjacent sclerotic bone. MRI shows lowintermediate T1 and intermediate-high T2 signal with bone marrow oedema. Which is the most likely diagnosis?
A. Giant cell tumour
B. Fibrous dysplasia
C. Enchondroma
D. Osteoblastoma
E. Aneurysmal bone cyst
D. Osteoblastoma
Osteoblastomas share clinical and histological features with osteoid osteomas and 3-12% occur in ribs.
- Regarding malignant fibrous histiocytoma:
A. Central mineralisation is common
B. Occur more often in bone than in soft tissue
C. Is the main primary malignant tumour of fibrous origin affecting bone
D. Most cases arise in Paget’s disease
E. Reactive changes are common
C. Is the main primary malignant tumour of fibrous origin affecting bone
Occur much more commonly in soft tissue than bone.
25% occur in pre-existing conditions such as Paget’s.
They usually present with insidious onset pain and swelling,
and central mineralisation and reactive changes are uncommon.
- Which of the following demonstrates the most uptake on PET/CT?
A. Primary bone lymphoma
B. Osteosarcoma
C. Chondrosarcoma
D. Enchondroma
E. Osteochondroma
A. Primary bone lymphoma
Greatest FDG uptake occurs in primary bone lymphoma and Ewing’s sarcoma.
Osteosarcoma demonstrates moderate uptake.
Most benign bone lesions are non-FDG avid, with the exception of high giant cell containing tumours (Giant Cell Tumors (GCT), osteoblastomas, aneurysmal bone cysts) and fibrous lesions (fibrous dysplasia).
1) A 34-year-old woman presents with pain and swelling of the right knee over the previous 2 months. Plain films demonstrate a wellcircumscribed, expansile, lytic lesion eccentrically located in the subarticular region of the right distal femur. The lesion has a narrow, non-sclerotic zone of transition. What is the most likely diagnosis?
a. giant cell tumour
b. enchondroma
c. fibrous cortical defect
d. fibrous dysplasia
e. aneurysmal bone cyst
a. giant cell tumour
The vast majority of giant cell tumours occur in patients with closed epiphyses, and although they may originate in the metaphysis, lesions typically involve the epiphysis and abut the subarticular surface.
They are classically eccentrically located lesions with a narrow zone of transition, no sclerosis, and no internal matrix mineralization.
Giant cell tumours tend to be locally aggressive, with a high recurrence rate after initial treatment.
Enchondromas are the commonest benign cystic lesion of the phalanges, though they are also seen in the long bones. However, those in the long bones almost always contain calcified chondroid matrix.
Aneurysmal bone cysts are often seen as an eccentric lytic expansile lesion, but patients are nearly all under the age of 30.
Monostotic fibrous dysplasia is more commonly seen in the proximal femur than distally, and lesions tend to have a sclerotic margin.
Fibrous cortical defects are asymptomatic lesions seen in children, which usually regress spontaneously, so they are only rarely seen after the age of 30. They typically appear as lytic lesions with a thin sclerotic border in the metaphysis of a long bone.
@# 12) A female adult patient with right shoulder pain is shown to have multiple markedly expansile lytic lesions within the scapula and clavicle secondary to metastatic malignant spread. Which of thefollowing is most likely to be the primary site of malignancy?
a. renal
b. breast
c. cervical
d. colon
e. bronchus
a. renal
The common cancers that typically metastasize to bone are breast, lung, thyroid, renal and prostate. Due to the high prevalence of colon cancer, even though only a relatively small proportion metastasizes to bone, it forms a significant proportion of bone metastases.
Prostatic metastases are typically sclerotic, whereas breast deposits are mixed.
Colonic bone metastases are usually lytic, with renal metastases typically lytic and expansile due to their highly vascular nature.
Other less frequent sources of lytic expansile metastases include thyroid, melanoma andphaeochromocytoma.
@# 13) A ‘fallen fragment’ seen within a lytic bone lesion is most commonly associated with which of the following?
a. aneurysmal bone cyst
b. unicameral (simple) bone cyst
c. giant cell tumour
d. eosinophilic granuloma
e. chondroblastoma
b. unicameral (simple) bone cyst
The fallen fragment is virtually pathognomonic for a simple bone cyst. It represents a fragment from a pathological fracture through the lesion, which has fallen to lie in a dependent location in the cyst matrix.
(CNS) 14) A 20-year-old man presents with gradual onset of neck pain and a painful lump in the upper neck posteriorly. Plain films show an apparent destructive lesion of the C2 vertebra. MRI shows a large lesion arising from the posterior elements of C2 and comprising multiple cysts with fluid–fluid levels, with preservation of the vertebral body. What is the most likely diagnosis?
a. aneurysmal bone cyst
b. giant cell tumour
c. chordoma
d. fibrous dysplasia
e. telangiectatic osteosarcoma
a. aneurysmal bone cyst
Aneurysmal bone cysts are seen mainly in patients under 20 years of age (75%) and affect the posterior elements when involving the spine. They may arise de novo, or secondary to another lesion such as a giant cell tumour (GCT) or fibrous dysplasia. Both GCTs and telangiectatic osteosarcomas may cause cysts with fluid–fluid levels on MRI, but GCTs arise from vertebral bodies and usually occur in the sacrum. Telangiectatic osteosarcomas usually affect long bones. Chordomas are malignant tumours that usually affect the vertebral body, with destruction and invasion of the discs and adjacent structures.
17) In imaging of focal bone lesions in the appendicular skeleton, which of the following radiographic features is most likely to indicate an aggressive or malignant process?
a. cortical expansion
b. lytic process
c. periosteal reaction
d. multiple lesions
e. wide zone of transition
e. wide zone of transition
The zone of transition relates to the interface between the tumour margin and the host bone. It is an extremely important discriminator, particularly for lytic lesions. Lesions with a well-defined margin (and therefore narrow zone of transition) are described as geographic and are usually non-aggressive, whereas those with a wide zone of transition are termed ‘permeative’ and are often malignant or aggressive (such as in osteomyelitis). Cortical expansion without destruction is seen in many benign or slow-growing conditions such as fibrous cortical defect and aneurysmal bone cyst. Many bone lesions, both benign and aggressive, are lytic. Periosteal reaction does not indicate an aggressive lesion as such, but the pattern of reaction can do so. Multiplicity is not an indicator of malignancy, as it can be seen in benign and self-limiting processes (such as multiple enchondromatosis and neurofibromatosis). Equally, a solitary lesion may be malignant.
19) The presence of punctate, ring-like or arcuate calcification in a lytic bone lesion on plain radiography is most commonly associated with which of the following matrix types?
a. osteoblastic
b. fibrous
c. cartilaginous
d. cellular
e. mixed
c. cartilaginous
Chondroid tumour matrix may or may not calcify, but, if it does, the pattern is characteristically in arcs or circles and is sometimes described as ‘popcorn’.
Osteoid matrix when calcified is usually dense and homogeneous like a cloud.
Calcified fibrous matrix has a characteristic ground-glass appearance,
whereas a cellular tumour usually does not show matrix calcification.
A mixed matrix will show mixed characteristics.
@# (Ped) 22) A 4-year-old boy is investigated for abnormal gait, with swelling and deformity of the right lower leg. Radiographs reveal epiphyseal irregularity and multiple abnormal ossifications around the medial portions of the distal femoral, and proximal and distal tibial epiphyses of the affected leg, with normal appearances of the lateral epiphyses and the whole of the contralateral lower limb. MRI demonstrates that the ossifications lie within the epiphyseal cartilage. What is the described condition?
a. hereditary multiple exostoses
b. Trevor’s disease
c. Ollier’s disease
d. Morquio’s syndrome
e. warfarin embryopathy
b. Trevor’s disease
Trevor’s disease (also called dysplasia epiphysealis hemimelica) is a rare developmental bone dysplasia.
It primarily occurs in children aged 2–4 years and affects boys more commonly than girls.
It shows a preponderance for the lower limbs, most commonly affecting the knee and ankle, and demonstrates single or multiple osteocartilaginous tumours arising from epiphyses.
The lesion is characteristically hemimelic, involving either the medial (two-thirds of cases) or lateral aspect of the ossification centres. Cases can be classified as localized, classic or generalized.
23) Plain radiographs of the hands in a young woman are performed for unilateral deformity. These show multiple lytic lesions in the medullary cavities of the tubular bones with cortical expansion and matrix mineralization, and associated Madelung deformity. The changes are unilateral. What is the most likely diagnosis?
a. Maffucci’s syndrome
b. Ollier’s disease
c. Trevor’s disease
d. Lichtenstein–Jaffe´ disease
e. Morquio’s syndrome
b. Ollier’s disease
Ollier’s disease or multiple enchondromatosis is characterized by the presence of benign intraosseous cartilaginous tumours. The estimated prevalence of the disease is 1 in 100 000. The distribution and number of lesions are variable, but are often unilateral and monomelic. Complications include pain, skeletal deformities, limb length discrepancy (including Madelung’s deformity) and the potential risk of malignant change to chondrosarcoma in 20–50% of cases. The condition in which enchondromas are associated with haemangiomas is known as Maffucci’s syndrome. Neither is usually inherited.
Trevor’s disease is an epiphyseal dysplasia,
whereas Lichtenstein–Jaffe´ disease is another name for fibrous dysplasia.
Morquio’s syndrome is one of the lysosomal storage disorders known as the mucopolysaccharidoses.
24) Of the following types of periosteal reaction, select the one most likely to indicate a benign process?
a. soap-bubble
b. sunray
c. hair-on-end
d. laminated
e. Codman’s triangle
a. soap-bubble
Periosteal reactions are usually a radiographic manifestation of underlying bone disease.
The term ‘soap bubble’ refers to expansion of the cortex without destruction by a lytic bone lesion. The intact cortex usually indicates a benign process, whereas cortical destruction is associated with malignant or aggressive lesions.
Sunray and hair-on-end reactions are spiculated forms of periosteal reaction that occur following periosteal elevation by tumour, with tumour preventing the subperiosteal space from filling with new bone.
Laminated or ‘onion-skin’ reaction occurs with both malignant and benign processes and indicates an intermittent or cyclical process.
Codman’s triangles are formed by elevation and then destruction of the periosteum. They are usually related to malignant tumours but can also be formed by aggressive benign processes.
35) A 19-year-old man presents to his general practitioner with a sudden onset of painful scoliosis. His pain improves with prescribed aspirin while awaiting MRI. MRI reveals a localized area of inflammatory change in the left pedicle of L1. Subsequent CT shows marked sclerosis in the same region with a 5 mm, cortically based central lucency. What is the most likely cause?
a. plasma cell cytoma
b. osteosarcoma
c. osteoid osteoma
d. Brodie’s abscess
e. lymphoma
c. osteoid osteoma
Osteoid osteoma accounts for 12% of benign neoplasms of bone. It is most commonly located in the cortex of long bones (50% in the femur and tibia) with 15% in the spine, typically the pedicle. It rarely exceeds 15 mm in size. Young men are most commonly affected, with pain as the predominant presenting feature due to the extensive inflammatory reaction and vascularity of the lesion. With spinal lesions this results in a painful positional scoliosis, though the majority of patients experience improvement of the pain with salicylates. The lucent central area or nidus represents the underlying pathological process, with the surrounding sclerosis representing reactive inflammatory change in normal bone. Treatment traditionally was surgical curettage, but radiologically guided percutaneous radiofrequency ablation is now used.
41) A 21-year-old man presents with right hip pain. He has a history of Ewing’s sarcoma of the right hemi-pelvis when aged 11, which was treated with limb-sparing surgery and chemoradiotherapy. Plain radiography shows well-defined regional sclerosis, and isotope bone scan demonstrates a corresponding photopenic area. What is the most likely cause of his pain?
a. recurrent Ewing’s sarcoma
b. heterotopic ossification
c. radiation necrosis
d. osteoarthritis
e. osteosarcoma
c. radiation necrosis
Ewing’s sarcoma is a relatively common malignant bone marrow tumour related to, and sharing a common chromosomal translocation with peripheral neuroectodermal tumours. It is a very aggressive tumour thatis expressed in the radiological findings of permeative osteolysis, cortical erosion, periostitis and a soft-tissue mass. It principally affects the lower half of the skeleton, with the most frequent location being metadiaphyseal in the femur, ilium, tibia, humerus, fibula and ribs. Both radio- and chemotherapy are used in treatment. Sclerosis within several months of treatment usually indicates bone healing or disease recurrence/persistence. Radiation-induced osteonecrosis is mainly an effect on the osteoblasts and is dose dependent (deterministic). It may be seen within the mandible within 1 year, but in other sites the latent period is longer and can be a number of years.
42) On MRI performed for a tender osteochondroma of the femoral metaphysis in an adult, which feature is most useful in determining the presence of malignant change?
a. thickness of the cartilage cap
b. lesion size
c. compression of local nerves
d. fracture of the stalk
e. bursa formation
a. thickness of the cartilage cap
Osteochondromas are the commonest bone tumours and are considered developmental exostoses rather than true neoplasms. They represent 20–50% of benign and 10–15% of all bone tumours. They are made up of cortical and medullary bone and an overlying cartilage cap. The cortex and medulla of the osteochondroma are continuous with the underlying host bone. They are typically orientated away from an adjacent distal joint. Lesions are frequently solitary, but multiple lesions are seen in hereditary multiple exostoses, an autosomal dominant syndrome. Malignant transformation occurs in 1% of solitary lesions and in 3–5% of patients with hereditary multiple exostoses. After skeletal maturity, continued lesion growth, particularly of the cartilage cap, is suggestive of malignant transformation. Although benign lesions may reach 10 cm in size, the cartilage cap should not exceed 1.5 cm after skeletal maturation. Any bone that develops by enchondral ossification may develop an osteochondroma, the long bones of the lower extremity being most frequently affected.
@# 53) Of the following subtypes of osteosarcoma, which is associated with the most favourable 5-year survival?
a. multicentric
b. periosteal
c. paraosteal
d. telangiectatic
e. soft-tissue
c. paraosteal
Osteosarcoma is the second most common primary malignancy of bone after multiple myeloma, accounting for 15% of all primary bone tumours. It usually affects those aged 10–30.
Ninety-five per cent are of the primary osseous type and, of these, paraosteal osteosarcoma has the most favourable 5-year survival rate of 80%.
Other osteosarcomas of the primary osseous type include periosteal (5-year survival rate 50%) and telangiectatic (less than 20%).
Multicentric refers to synchronous osteoblastic osteosarcomas at multiple sites. It occurs exclusively in children aged 5–10, and carries an extremely poor prognosis.
The soft-tissue type is rare, representing only 1.2% of all soft-tissue tumours. These lesions are primary soft-tissue tumours with no attachment to bone. Death occurs within 3 years in the majority of cases, tumour size being the major predictor of outcome.
@# 54) A 30-year-old woman undergoes plain radiographic imaging of the hand for a palpable, painful hard lump on the dorsum. Plain radiographs show a well-defined bony mass applied closely to the diaphysis of the second metacarpal. CT shows a wide-based pedunculated lesion with a perpendicular orientation to the diaphysis, no cartilage cap and a matrix of mature trabeculated bone. What is the most likely diagnosis?
a. osteochondroma
b. multiple osteocartilaginous exostoses
c. bizarre paraosteal osteochondromatous proliferation
d. Codman’s tumour
e. dysplasia epiphysealis hemimelica
c. bizarre paraosteal osteochondromatous proliferation
Bizarre paraosteal osteochondromatous proliferation (also known as Nora’s lesion) is a rare condition usually seen in adults in the third and fourth decades of life. Osteochondroma-like lesions are seen most commonly at the proximal and middle phalanges, followed by the metacarpals and metatarsals. A relationship to trauma has been suggested but not proven. Other locations that may be affected include the long bones (especially those of the upper extremity), skull and jaw. It is thought to be a similar process to that which gives rise to lesions in myositis ossificans, reactive periostitis and subungual exostosis. On plain radiographs, a well-defined bony mass is seen attached to the surface of the parent bone.
Features differentiating this from osteochondroma are the absence of angulation away from the nearby physis and a wide base.
59) A middle-aged woman, known to suffer from polyostotic fibrous dysplasia, presents with a palpable, 3 cm, soft-tissue mass in the upper left thigh. MRI shows a relatively homogeneous, smooth, well-defined lesion located in an atrophic quadriceps muscle, which returns low signal on T1W images and high signal on T2W images. Following administration of intravenous gadolinium, the lesion shows moderately intense heterogeneous enhancement. What is the most likely pathological nature of the soft-tissue lesion?
a. soft-tissue myxoma
b. malignant fibrous histiocytoma
c. soft-tissue cavernous haemangioma
d. multiple lipomatosis
e. rhabdomyosarcoma
a. soft-tissue myxoma
The association of fibrous dysplasia and soft-tissue myxoma is well established and is commonly termed Mazabraud’s syndrome. The key is identifying the relationship between the bone and soft-tissue pathology, with the osseous features of fibrous dysplasia usually preceding the formation of a soft-tissue mass. The condition is non-familial and more commonly affects women, the thigh being the most common location. Typical MRI appearances are of a well-defined lesion with signal intensity similar to water, and often a fat rind or adjacent muscle high signal on T2W images is seen. Although uncommon, there have been reported cases of malignant change into osteosarcoma.
78) A 30-year-old man undergoes MRI of the whole of the left lower limb and pelvis for a mid-femoral destructive lytic lesion identified on radiography that is thought to represent a primary bone tumour. MRI shows that the disease is confined to the femur with a 5 cm diaphyseal lesion and a 1 cm proximal metaphyseal skip lesion. No enlarged lymph nodes are identified. CT scans of the chest, abdomen and pelvis show two metastatic nodules in the lower lobe of the left lung. Subsequent biopsy confirms the diagnosis of osteosarcoma. The cancer is correctly staged as which of the following?
a. T1 N0 M0
b. T1 N0 M1a
c. T2 N0 M1b
d. T3 N0 M1a
e. T3 N0 M1b
d. T3 N0 M1a
Complete staging of primary bone sarcomas is unusual in that it also incorporates the histological staging once tissue diagnosis via biopsy or surgical resection is available. The local TNM classification is T1 (single lesion less than 8 cm), T2 (single lesion over 8 cm) or T3 (skip lesions of any size). Nodal staging is N0 (no nodes) or N1 (any number of metastatic nodes). Metastatic spread is staged, accordingly, as M0 (no metastases), M1a (metastases to lung) or M1b (any other distant site). Once histology is available, tumours can be staged I–IV.
(Ped) 90) An 8-year-old boy with a 3-month history of increasing chest wall pain presents with a tender lump on the chest wall. Imaging of the chest shows a large inhomogeneous mass arising from a rib with a large intrathoracic component and preservation of tissue planes. There is associated rib destruction and a lamellated periosteal reaction is seen. What is the most likely diagnosis?
a. Ewing’s sarcoma
b. neuroblastoma
c. Hodgkin’s disease
d. osteomyelitis
e. hamartoma of chest wall
a. Ewing’s sarcoma
Ewing’s sarcoma is the commonest malignant bone tumour in children, and the ribs are involved in 30% of cases in children under 10. It is the commonest malignant chest wall tumour. Neuroblastoma presents in children under 5 as a well-defined, soft-tissue mass that may calcify and erodes/splays the ribs. Hodgkin’s disease presents in young adults, and usually involves bones by secondary involvement with direct invasion of sternum or ribs. Osteomyelitis presents at any age with a shorter history (usually less than 2 weeks), and imaging shows rib destruction with a relatively small mass and loss of tissue planes. Hamartoma of the chest wall presents in the first year of life as an extrapleural mass, causing partial/complete destruction of adjacent ribs. Significant calcification and compression of the adjacent lung occur.
91) A 70-year-old man undergoes CT of the skull for investigation of clinically apparent macrocephaly confirmed on skull radiography.You are asked by the referring clinician to review the images. Which finding is most likely to support a diagnosis of fibrous dysplasia over Paget’s disease?
a. widened diploe¨
b. asymmetrical involvement of the skull
c. sparing of the paranasal sinuses
d. osteoporosis
e. ground-glass medulla
e. ground-glass medulla
A ground-glass appearance is characteristic of fibrous dysplasia and is the most useful discriminating factor. Other features of fibrous dysplasia of the skull that can help distinguish it from Paget’s disease are symmetry of distribution, presence of a soft-tissue mass, cyst-like changes, thickness of the cranial cortices, and involvement of the paranasal sinuses, maxilla, sphenoid, orbits and nasal cavity.
93) An elderly man undergoes 99mTc-labelled diphosphonate bone scintigraphy. There is no uptake of tracer in the soft tissues, urinary tract or appendicular skeleton, but the axial skeleton shows diffuse homogeneous tracer uptake. No focal lesions are seen. What is the most likely cause of these appearances?
a. prostatic metastases
b. renal osteodystrophy
c. Paget’s disease
d. mastocytosis
e. myelofibrosis
a. prostatic metastases
The resulting pattern following diffuse uptake of 99mTc-labelled diphosphonates in the axial skeleton, with little or no uptake of tracer in the soft tissues or urinary tract, is frequently referred to as a superscan. When there is little uptake in the limbs, the cause is most likely to be diffuse metastases in the axial skeleton, most commonly prostatic or breast. Uptake in metabolic bone disease is more uniform in appearance, and extends into the distal appendicular skeleton. Intense calvarial uptake disproportionate to that in the remainder of the skeleton may also be seen. The most important factor is to recognize the scan as abnormal in the absence of focal lesions. The lack of renal uptake (absent kidney sign) is a useful discriminator.
100) Plain radiographs of the femur performed for pain reveal a centrally located lucent lesion in the medulla with a partially calcified matrix. Which of the following features favours a diagnosis of chondrosarcoma over enchondroma?
a. arc-and-ring matrix calcification
b. ground-glass matrix
c. multiple lesions
d. deep endosteal scalloping
e. lesion size over 5 cm
d. deep endosteal scalloping
Distinction of enchondroma and intramedullary chondrosarcoma in the appendicular skeleton proximal to the metacarpals/-tarsals is difficult radiologically. A series of 187 patients showed that chondrosarcoma was associated with endosteal scalloping, with scalloping involving more than two-thirds of the extent of the lesion being strongly suggestive of malignancy. Other powerful discriminating factors identified as favouring chondrosarcoma were cortical destruction, soft-tissue mass, periosteal reaction, radionuclide uptake at scintigraphy and pain associated with the lesion. Chondrosarcoma also tended to be larger with a mean size of 10 cm compared with 6.7 cm for enchondroma. A ground-glass matrix with arcuate calcification is characteristic of both types of cartilaginous lesion. Multiple lesions may be seen in both malignancy and enchondromatosis (Ollier’s disease).
1 A plain radiograph reveals a well-defined lucent lesion within the metaphysic and epiphysis of the distal femur. There is eccentric expansion and the cortex is thin but intact. It does not reach the articular surface. CT reveals fluid-fluid levels. Which of the following is the most likely cause?
(a) Giant cell tumour
(b) Aneurysmal bone cyst
(c) Enchondroma
(d) Non-ossifying fibroma
(e) Chondromyxoid fibroma
(b) Aneurysmal bone cyst
Of the conditions that typically cause lucent, eccentrically expanded lesions, only GCTs and ABCs have fluid-fluid levels on CT imaging. As GCTs do not reach the articular surface, this is most likely to be an ABC.
12 A 27 year old undergoes a CXR as part of an occupational assessment. The CXR shows a solitary expansile right 5th posterior rib mass. CT confirms the mass is arising from the rib and that it shows no aggressive features.
What is the likeliest diagnosis?
(a) Exostosis of the rib
(b) Benign cortical defect
(c) Langerhans cell histiocytosis
(d) Fibrous dysplasia
(e) Osteoblastoma
(d) Fibrous dysplasia
Fibrous dysplasia is the commonest benign rib tumour. Second most common is osteochondroma/bony exostosis but this typically occurs at the costochondral junction. Other benign possibilities include GCT and aneurysmal bone cyst.
13 A calcified mass is seen on a plain radiograph of a young man’s femur. The mass appears to be centred within the soft tissues of the thigh and the calcification is more prominent on the periphery of the mass. There is a radiolucent zone separating the lesion from the underlying bone, the cortex of which appears unaffected. Which of the following is the most likely diagnosis?
(a) Myositis ossificans
(b) Parosteal osteosarcoma
(c) Juxtacortical chondroma
(d) Osteochondroma
(e) Rhabdomyosarcoma
(a) Myositis ossificans
Myositis ossificans is a form of heterotopic bone formation within skeletal muscle, usually resulting from blunt trauma. Although parosteal osteosarcoma can have similar appearances, myositis ossificans typically has denser calcification in the periphery; osteosarcoma shows the reverse phenomenon, with denser calcification centrally. Juxtacortical chondroma typically scallops the underlying cortex. An osteochondroma is continuous with the underlying bone.
23 A 7 year old boy is brought to the GP by his parents, having noticed soft, blue-coloured growths on his right hand. The hand X-ray reveals multiple enchondromas. Which of the following features would confirm Mafucci’s syndrome as the diagnosis rather than Ollier’s disease?
(a) A first degree relative also affected
(b) Bilateral, predominantly symmetrical disease
(c) A discrepancy in arm length
(d) Sarcomatous degeneration
(e) Soft tissue haemangiomas
(e) Soft tissue haemangiomas
Both conditions describe multiple enchondromas affecting the hands and/or feet, and both tend to be unilateral; neither has a genetic component. Both conditions can lead to shortening of the involved arm/leg, resulting in length discrepancy. Malignant degeneration can be to osteosarcoma (young adults), or chondro/fibrosarcoma (older patients); it is more common in Mafucci’s syndrome, but is still seen in 5-30% of cases of Ollier’s disease. Maffucci’s syndrome describes enchondromas with additional multiple soft tissue haemangiomas, if bilateral there is marked asymmetry.
35 A 50 year old man presents with knee pain. Plain raqiographs show an 8 cm lytic lesion within the distal femoral metaphysis with endosteal scalloping and cortical thickening. CT shows matrix mineralisation.
Which of the following features does not favour a diagnosis of chondrosarcoma over enchondroma?
(a) The patient’s age
(b) The patient’s sex
(c) The lesion size
(d) The lesion site
(e) The CT findings
(e) The CT findings
Enchondromas present in a slightly younger age group and are more common in females. They typically affect the bones of the hands and feet and are usually less than 5 cm in size. Although both lesions show matrix mineralisation, this feature is slightly commoner in enchondromas. Other features to favour chondrosarcoma over enchondroma include presentation with a mass, cortical destruction and the presence of a soft tissue mass.
44 A 38· year old woman presents with a palpable lump in her thigh. Plain films show a lobulated ossified mass lying posterior to the femur with a connection to the cortex. The centre of the lesion is denser than the periphery. MRI shows a large associated soft tissue component. What is the likeliest diagnosis?
(a) Myositis ossificans
(b) Osteochondroma
(c) Parosteal osteosarcoma
(d) Periosteal osteosarcoma
(e) Extraosseous osteosarcoma
(c) Parosteal osteosarcoma
Parosteal osteosarcomas have the best prognosis of all osteosarcomas. If no stalk can be clearly identified they can be distinguished from myositis ossificans by the relative density of the centre of the ossified part of the lesion.
47 A 40 year old man presents with heel pain. Lateral radiograph of the foot reveals a well-defined 3 cm lesion located between the anterior and middle thirds of the calcaneus. The lesion is radiolucent with a thin rim of sclerosis and central calcification. What is the likely diagnosis?
(a) Desmoplastic fibroma
(b) Giant cell tumour
(c) lntraosseous lipoma
(d) Osteoid osteoma
(e) Unicameral bone cyst
(c) lntraosseous lipoma
lntraosseous lipomas are rare bone tumours; they are often asymptomatic and present incidental, but can be associated with pain. The commonest locations are within the proximal femur (Ward’s triangle) and in the area of the calcaneus described. In these areas there is a relative paucity of trabecular bone and it is thought that this leads to an ‘overshoot’ phenomenon during the transition of haematopoietic to fatty marrow, with the resultant formation of the lipoma. Central or ring calcification in a lucent lesion in this location of the calcaneus is said to be pathognomonic of an intraosseous lipoma and allows its distinction from a UBC. If clinical doubt persists MR imaging can be used for further clarification and to confirm the presence of fat.
48 Regarding osteoblastomas, which of the following is true?
(a) An expansile appearance on plain film implies malignancy
(b) Matrix calcification is a common plain film feature
(c) They result in scoliosis more commonly than osteoid osteoma ‘
(d) They rarely grow beyond 2 cm
(e) They usually present in the 6th-7th decades
(b) Matrix calcification is a common plain film feature
Osteoblastomas are uncommon primary bone tumours (< 1 %). 90% occur in 2nd - 3rd decades, although cases have been documented up to 72 years. They are histologically similar to osteoid osteoma but less well organised and by definition larger (> 2 cm). The majority (30- 40%) of cases occur in the spine, with a slight predominance for the posterior elements (55%). An expansile lesion in osteoblastoma is not typically associated with malignancy. Scoliosis can occur in both and is typically painful, but occurs more commonly in osteoid osteoma, where the scoliosis results from muscle spasm secondary to the inflammatory mediators produced. Osteoblastomas are not radiosensitive and surgical excision is performed in most cases, however, recurrence is seen in up to 50%.
50 A 3 month old infant presents with tender, hard swellings over a number of bones. Radiographs reveal a cortical hyperostosis and marked, diffuse, symmetrical periosteal reaction of the clavicles, ribs and mandible. Which of the following is the most likely diagnosis?
(a) Rickets
(b) Caffey’s disease
(c) Hypothyroidism
(d) Scurvy
(e) Ulcerative colitis
(b) Caffey’s disease
The appearances are typical of Caffey’s disease, also known as infantile cortical hyperostosis. Scurvy and rickets are unlikely to produce this picture in those < 6 months old.
1 You review a plain radiograph of the left femur of a 16 year old patient and note a lesion with a wide zone of transition and a marked ‘sunburst’ periosteal reaction. Which of the following is the most likely diagnosis?
(a) Aneurysmal bone cyst
(b) Ewing’s sarcoma
(c) Osteosarcoma
(d) Fibrosarcoma
(e) Osteoid osteoma
(c) Osteosarcoma
Of the above list, osteosarcoma is the most likely. The periosteal reaction (and wide zone of transition) indicates an aggressive lesion. Ewing’s sarcoma is more common in the 1-10 year old age group, and fibrosarcoma in the 30-60 year old age group.
8 A 23 year old woman complains of anterior chest wall pain. CXR shows a large expansile mass arising from the left 3rd rib. CT confirms the mass is solitary and demonstrates whorled areas of ‘rings and arcs’ calcification with no soft tissue component. Which of the following is the most likely diagnosis?
(a) Osteosarcoma
(b) Osteoblastoma
(c) Chondrosarcoma
(d) Askin tumour
(e) Plasmacytoma
(c) Chondrosarcoma
Rings and arcs of calcification indicate a chondroid matrix. Chondrosarcoma is the likeliest primary rib tumour in this age group. Other primary malignant tumours include plasmacytoma and lymphoma.
19 A plain radiograph of a 20 year old’s knee shows a well defined lesion in the distal femoral epiphysis. It is lytic, with a narrow zone of transition and a well defined sclerotic rim. The lesion does not reach the articular surface, and is not expansile. Which of the following conditions is the most likely?
(a) Aneurysmal bone cyst
(b) Chondroblastoma
(c) Giant cell tumour
(d) Simple bone cyst
(e) Metastasis
(b) Chondroblastoma
Chondroblastomas almost invariably occur in the epiphyses, and 90% occur in those under 30 years old. Lesions to consider in this location and age group include: infection, chondroblastomas, GCTs and, less commonly, ABCs and eosinophilic granulomas. With regards to the other conditions mentioned: GCTs abut the articular surface; ABCs are almost always expansile; simple bone cysts are not epiphyseal; metastases are unlikely in a 20 year old.
23 A 15 year old girl presents with a history of several months leg pain, worse at night which is relieved by salicylates. Plain films show a 1.3 cm lesion in the proximal tibial shaft which has a round central lucency with surrounding sclerosis. What is the likeliest diagnosis?
(a) Osteosarcoma
(b) Brodie abscess
(c) Aneurysmal bone cyst
(d) Osteoid osteoma
(e) Stress fracture
(d) Osteoid osteoma
The classical finding is that of a central, usually lucent nidus of less than 1.5 cm in size with varying degrees of surrounding sclerosis. There is often a typical clinical picture which enables differentiation from a Brodie abscess.
31 A patient has widespread metastatic disease. The skeletal metastases are sclerotic. Which of the following primary cancers most commonly produce sclerotic metastases?
(a) Renal cell carcinoma
(b) Carcinoid
(c) Wilm’s tumour
(d) Ovarian carcinoma
(e) Melanoma
(b) Carcinoid
Sclerotic metastases are typically the result of: prostate carcinoma, carcinoid, transitional cell carcinoma, breast (mixed), medulloblastoma, colon (occasionally), and lymphoma.
37 A 32 year old woman presents after minor trauma with a lump over the midshaft of her left tibia. Plain films show an 8 cm multilocular, slightly expansile, predominantly lytic lesion with a sclerotic margin, and a narrow zone of transition. The lesionis orientated longitudinally along the anterior tibial diaphysis. What is the most likely diagnosis?
(a) Adamantinoma
(b) Eosinophilic granuloma
(c) Fibrous dysplasia
(d) Non-ossifying fibroma
(e) Chondro/nyxoid fibroma
(a) Adamantinoma
These are locally aggressive lesions which tend to recur and after several recurrences can metastasize to lungs. The main differential diagnosis for this ‘soap-bubble’ like appearance is fibrous dysplasia, but this usually presents in a slightly younger age group.
43 A 70 year old woman presents with a longstanding right sided painless swelling on her back. US shows a lesion with an array of linear strands against an echogenic background. MRI shows the lesion lies between the posterior chest wall and the inferomedial bor£1er of the scapula. It is well defined, has signal characteristics similar to surrounding skeletal muscle and has linear areas of high signal. It enhances heterogeneously after the administration of i. v. gadolinium. What is the likeliest diagnosis?
(a) Liposarcoma
(b) Extra-abdominal desmoid
(c) Metastasis
(d) Elastofibroma
(e) Lipoma
(d) Elastofibroma
Elastofibroma is benign tumour forming as a reaction to mechanical friction most commonly seen in the subscapular area. Recent evidence suggests a genetic component. It is bilateral in 25%. Its site, presentation and imaging characteristics are usually typical, however, excision is still performed if there is any doubt with regards to malignant transformation.
52 A 31 year old previously well woman presents with pain just above the knee. Plain radiographs show a fracture through a well circumscribed, expansile, solitary lytic bone lesion with a narrow zone of transition. The lesion involves the’·articular surface but does not extend into the joint space. What is the likeliest diagnosis?
(a) Chondroblastoma
(b) Fibrous dysplasia
(c) Giant cell tumour
(d) Eosinophilic granuloma
(e) Aneurysmal bone cyst
(c) Giant cell tumour
This is the characteristic patient age and site of GCT, where the unfused physis acts as a barrier to spread of the lesion. After fusion, extension to within 1 cm of the articular surface is the commonest pattern, although transarticular spread has been reported. It can have either a ‘soap bubble’ like appearance or, as described here, a uniform lytic appearance. 10% present with pathological fractures.
55 A 3 year old child of short stature is found to have numerous bony exostoses on plain radiography. Which of the following statements is not true?
(a) Hereditary transmission is autosomal dominant
(b) Malignant transformation to osteosarcoma occurs in 1 %
(c) The distal femur and proximal tibia are most commonly involved bones
(d) It is more common in males
(e) There is an association with polydactyly
(b) Malignant transformation to osteosarcoma occurs in 1 %
Hereditary multiple exostoses (also known as diaphyseal aclasia) is an autosomal dominant condition characterised by multiple exostoses. Malignant transformation to chondrosarcoma occurs in 1-5%.
61 A 10 year old girl presents with precocious puberty and café au lait spots. McCune-Albright syndrome is suspected. Which of the following features would you not expect to see?
(a) A ground glass lesion in the medullary cavity of the femur
(b) Champagne glass appearance of the pelvis
(c) Endosteal scalloping of the femur with intervening normal cortex
(d) Cortical expansion of the ribs
(e) Increased uptake of a rib lesion on bone scintigraphy
(b) Champagne glass appearance of the pelvis
McCune-Albright syndrome is a form of fibrous dysplasia. It is seen in 10% of cases. Radiologically, it is characterised by a polyostotic, unilateral pattern of involvement. The skull is commonly involved. A champagne glass appearance of the pelvis is seen in achondroplasia.
66 A 20 year old man presents with a swelling in his thigh. He recalls innocuous trauma at this site a few weeks earlier. Plain films suggest a soft tissue mass with peripheral calcification at the level of the mid femur with a radiolucent zone separating the lesion from cortex. MRI shows a heterogeneous, well defined soft tissue mass, isointense to muscle on T1W and hyperintense on T2W, with curvilinear peripheral ar’e as of low signal intensity.
Which of the following is the likeliest diagnosis?
(a) Myositis ossificans
(b) Parosteal sarcoma
(c) Tumoural calcinosis
(d) Rhabdomyosarcoma
e) Chondrosarcoma
(a) Myositis ossificans
These are the typical findings of myositis ossificans. Although· in the acute stages, it can be confused with other entities, as it matures and calcifies, it can be discriminated from osteosarcomas by the pattern of peripheral calcification and from parosteal sarcomas by the lack of a connecting stalk to the cortex.
71 A 62 year old man presents with a history of a lump in his thigh which he feels has enlarged over several months. On plain films a soft tissue mass with punctuate calcification and adjacent cortical erosion is seen. At MRI the mass is confirmed to be in the soft tissues, is heterogeneous in signal intensity but is generally isointense to muscle on T1W and hyperintense on T2W. What is the likeliest diagnosis?
(a) Parosteal sarcoma
(b) Liposarcoma
(c) Lipoma
(d) Malignant fibrous histiocytoma
(e) Rhabdomyosarcoma
(d) Malignant fibrous histiocytoma
MFH is the commonest primary malignant soft tissue tumour of later life. It presents as a painless progressively enlarging mass. Calcification is seen in up to 20%. Cortical erosion of adjacent bone is a suggestive feature.
73 A 30 year old undergoes a shoulder x-ray following a fall. No fracture is identified. However, note is made of acromioclavicular joint erosion. Which of the following is least likely?
(a) Lymphoma
(b) Hyperparathyroidism
(c) Rheumatoid arthritis
(d) Scleroderma
(e) Fibrous dysplasia
(e) Fibrous dysplasia
Other causes include gout, myeloma, osteomyelitis and previous trauma.
75 A 13 year old boy presents with a long history of a dull ache_ in his hip. Plain radiographs show a 4cm eccentric lytic lesion of the proximal femoral epiphysis extending to involve the proximal metaphysis. It has a lobulated, well-defined sclerotic margin and areas of calcification within it. There is significant surrounding periosteal reaction. Which of the following is the likeliest diagnosis?
(a) Enchondroma
(b) Chondromyxoid fibroma
(c) Chondrosarcoma
(d) Chondroblastoma
(e) Giant cell tumour
(d) Chondroblastoma
The main differential diagnosis for epiphyseal lesions would be GCT. However, these typically arise in a slightly older age group and only cross the physis once it has fused. Chondrosarcomas occur in an older age group (median age 45 years) and chondromyxoid fibromas are rare (usually but not exclusively metaphyseal) cartilaginous tumours arising from the cortex.
- A 17 year old girl presents with pain in the distal forearm which has worsened over the last six to eight weeks. Plain films show an eccentric lytic radiolucency in the distal radius with a soap-bubble appearance. The most likely pathology is:
a. Enchondroma
b. Aneurysmal bone cyst
c. Simple bone cyst
d. Fibrous dysplasia
e. Chondroblastoma
- b. Aneurysmal bone cyst
Aneurysmal bone cyst is most common in females and 75% occur under 20 years of age. The classic presentation is of pain of relatively acute onset with a rapid increase in severity over 6–12 weeks. Common locations include the spine, with a slight preponderance for the posterior elements, and the metaphysis of long bones – femur, tibia, humerus and fibula. The lesion is usually expansile with thin internal trabeculations giving it the characteristic soap-bubble appearance.
- A 20 year old man presents with an increasingly painful right thigh which is worse at night. Plain films of the area show a lucent area measuring approximately 8–9mm in the distal femur surrounded by extensive sclerosis. The most likely diagnosis is:
a. Osteoblastoma
b. Giant cell tumour
c. Brodie’s abscess
d. Osteoid osteoma
e. Chondroblastoma
- d. Osteoid osteoma
This most commonly presents in the second and third decades. The male:female ratio is 2.5:1. Classically it presents with increasing pain which is worse at night and often relieved with aspirin. Spinal lesions often lead to painful scoliosis. Almost any site in the body may be affected but the most common regions are the lower limb and spine.
(ped) 9. A ten year old boy presents with severe localised pain in the distal femur with an associated swelling. Blood films show a leucocytosis and anaemia. At the time of diagnosis he has both lung and bone metastases. The most likely diagnosis is:
a. Osteosarcoma
b. Giant cell tumour
c. Lymphoma
d. Ewing’s sarcoma
e. Clear cell sarcoma
- d. Ewing’s sarcoma
`
Ninety-five per cent present between 4 and 25 years of age. Sixty per cent occur in the long bones, mainly in the metadiaphysis and have a typical moth-eaten destructive appearance on plain film. Metastases to the lung, bone and regional lymph nodes are present in 11–30% of cases at the time of diagnosis.
- A 22 year old man presents to his GP with pain in his right knee which is gradually worsening in severity and is relatively resistant to analgesia. MRI of the knee demonstrates an area of geographic bone destruction in the distal femur with a wide zone of transition. There is marked aneurysmal dilatation of the bone and a fluid-fluid level is present within the lesion. The most likely diagnosis is:
a. Plasmacytoma
b. Simple bone cyst
c. Giant cell tumour
d. Telangiectatic osteosarcoma
e. Parosteal osteosarcoma
- d. Telangiectatic osteosarcoma
With the MRI finding described, the most likely explanation is that the lesion is a telangiectatic osteosarcoma. This is a rare type of osteosarcoma with a mean age at presentation of 20 years. The most common site is around the knee (62%). Fluid-fluid levels are also seen in giant cell tumours and aneurysmal bone cysts.
- A 74 year old woman with back pain presents to her GP. Initial plain radiographs of her spine show multiple sclerotic metastatic lesions. The most likely primary tumour would be:
a. Renal cell carcinoma
b. Melanoma
c. Bronchial carcinoid
d. Bladder
e. Colorectal carcinoma
- c. Bronchial carcinoid
The most likely from the above list is a bronchial carcinoid. In men the most likely cause would be prostate. All other conditions are likely to produce lytic metastases than sclerotic.
- An 18 year old student who fell down two stairs and landed on her left knee attends A&E complaining of generalised knee pain but is able to weight bear. No acute bony injury is demonstrated on plain film, however a pedunculated lesion arising from the femoral metaphysis and extending away from the knee joint is seen. The lesion shows continuity with both the marrow and the cortex. The most likely diagnosis is:
a. Osteochondroma
b. Osteoblastoma
c. Osteoid osteoma
d. Chondroblastoma
e. Chondromyxoid fibroma
- a. Osteochondroma
The description is classic for an osteochondroma or osteocartilagenous exostosis. These lesions are the most common benign growths of the skeleton, are usually found incidentally and are usually asymptomatic unless complications arise. Complications include fracture, vascular compromise, bursa formation and malignant transformation into chondrosarcoma.
- A 25 year old woman attends A&E after falling onto her right hand. A plain film of her hand is taken in order to exclude fracture. No bony injury is seen. On examination, however, there is painless swelling of the right index finger which she says has been present for a few weeks. Incidental note is made of a small central lesion within the medullary cavity of the middle phalanx of the index finger. There is no cortical breakthrough or periosteal reaction but there is bulbous expansion of the bone with thinning of the cortex. The lesion contains dystrophic calcifications. This is most likely to represent:
a. Giant cell tumour of the tendon sheath
b. Unicameral bone cyst
c. Brown tumour
d. Enchondroma
e. Epidermal inclusion cyst
- d. Enchondroma
This lesion is most likely to be an enchondroma. This is a benign cartilaginous growth in the medullary cavity and is usually asymptomatic. It most commonly occurs in the small bones of the hands and wrist but may also occur in the proximal humerus and proximal femur. Epidermoid inclusion cysts are usually in the distal phalangeal tuft and there is often a history of trauma. A bone cyst would be unusual in the phalanges.
(Ped) 39. A 12 year old boy attends A&E after falling off his bike. He complains of pain in the right hand. Plain radiographs show no bony injury. However, a small well-rounded lesion is seen in the proximal phalanx of the index finger. This has a ground glass appearance and contains dystrophic calcifications. There is no cortical breakthrough or periosteal reaction. The most likely cause of this lesion is:
a. Simple bone cyst
b. Aneurysmal bone cyst
c. Enchondroma
d. Epidermoid inclusion cyst
e. Fibrous dysplasia
- c. Enchondroma
The most common location of these benign lesions is the tubular bones of the wrist and hands, and they are usually asymptomatic and therefore diagnosed incidentally. Of the other lesions mentioned, ABC, simple bone cyst and fibrous dysplasia are rare in the hands. An epidermoid inclusion cyst is most likely to occur at the distal phalanx.
- A 20 year old student complains of a six-week history of pain and tenderness in his right thigh associated with a soft-tissue mass. There is no definite history of trauma. CT of the region shows a mass in the right distal femur with well-defined mineralization at the periphery and a less distinct lucent centre. On plain film, there is faint calcification within the lesion and a radiolucent zone separating the lesion from bone. The most likely cause is:
a. Tumoural calcinosis
b. Osteomyelitis
c. Myositis ossificans
d. Parosteal sarcoma
e. Osteosarcoma
- c. Myositis ossificans
Often there is no distinct history of trauma, although this is the most common cause. It usually occurs in the large muscles of the extremities and in the early stages it can be difficult to distinguish from soft-tissue sarcomas. It is, however, separate from bone, unlike parosteal sarcoma and post-traumatic periostitis. This is a self-limiting condition, most commonly occurring in young athletic adults, with resorption occurring in approximately one year.
- A 60 year old man is referred for an MRI of his left upper leg after noticing a slowly enlarging firm mass measuring approximately 7–8 cm in maximum diameter. The mass is located in the quadriceps muscle group and is causing cortical erosion of adjacent bone. There are poorly defined calcifications within it and MR shows a poorly defined lesion which is isointense to muscle on T1-weighted imaging and hyperintense on T2-weighted imaging. The most likely diagnosis is:
a. Malignant fibrous histiocytoma
b. Benign fibrous histiocytoma
c. Liposarcoma
d. Fibrosarcoma
e. Elastofibroma
- a. Malignant fibrous histiocytoma
Soft-tissue malignant fibrous histiocytoma is the most common primary malignant softtissue tumour of later adulthood. It is most commonly seen in the lower extremities. It has a metastatic rate of 42% and most commonly metastasises to the lung. Osseous malignant fibrous histiocytoma presents as a painful, tender, rapidly enlarging mass and most commonly arises in the metaphysis of long bones.
- An 18 year old man undergoes a Tc MDP bone scan to investigate pain in the right hip. A ‘hot’ lesion is seen in the right proximal femur. No other lesions are seen. Which of the following lesions would appear as ‘hot’ on a Tc MDP bone scan?
a. Osteopoikilosis
b. Fibrous cortical defect
c. Acute fracture within 12 hours of injury
d. Fibrous dysplasia
e. Haemangioma
- d. Fibrous dysplasia
The most common site of monostotic fibrous dysplasia is the ribs, followed by proximal femur and craniofacial bones. Three-quarters of cases present before age 30. Other benign lesions causing a ‘hot’ on bone scan include Paget’s disease, brown tumours, aneurysmal bone cysts, osteoid osteoma and chondroblastoma. Acute fractures are not usually ‘hot’ until after the first 24–48 hours.
- A 29 year old woman presents with a painful right knee which has been worsening over the previous few weeks. A plain film of the right knee shows an oval expansile lesion with a radiolucent centre in the metaphyseal region of the proximal tibia. There is a sclerotic margin and geographic bone destruction. There are internal septations and stippled calcification. There is no periosteal reaction. The most likely diagnosis is:
a. Non-ossifying fibroma
b. Chondroblastoma
c. Giant cell tumour
d. Chondromyxoid fibroma
e. Chondrosarcoma
- d. Chondromyxoid fibroma
This is most commonly seen in the second and third decades and the most common site is the long bones, most often the proximal tibia and distal femur. Non-ossifying fibroma is usually asymptomatic. The appearances of a chondroblastoma would be similar but this would most likely be epiphyseal in location and usually presents in a slightly younger age group.
- A 53 year old woman attends A&E with a short history of dull right heel pain. She is otherwise fit and well and there is no history of trauma. Plain radiographs of the right foot and ankle reveal a 2 cm expansile non-aggressive lesion in the calcaneum. It has a thin, well-defined sclerotic border. There is no periosteal reaction but there is a small calcified central nidus. The most likely cause of the lesion is:
a. Aneurysmal bone cyst
b. Intra-osseous lipoma
c. Lipoblastoma
d. Fibrous dysplasia
e. Desmoplastic fibroma
- b. Intra-osseous lipoma
The calcaneum is a common location for an intra-osseous lipoma. They do, however, also occur in the extremities, skull and mandible. There is no periosteal reaction unless there is an associated fracture. Imaging features would be similar to those of a unicameral bone cyst. They are often asymptomatic but can present with localised bone pain.
QUESTION 4
A previously well 80-year-old woman sustains a subcapital fracture of the right neck of femur following a fall onto hard ground. The plain film reveals multiple lytic lesions within the pelvic bones and proximal femora, which are highly suspicious for bone metastases. What is the most likely occult primary lesion?
A Carcinoma of the bladder
B Carcinoma of the breast
C Carcinoma of the bronchus
D Carcinoma of the colon
E Carcinoma of the stomach
B Carcinoma of the breast
A 43-year-old man is investigated for pain related to his left arm. Plain radiography demonstrates a well-defined, lytic lesion in the proximal humerus, with chondroid matrix mineralisation and a narrow zone of transition. There is deep endosteal cortical scalloping and the suggestion of bone expansion. What is the most likely diagnosis?
A Chondroblastoma
B Chondroma
C Chondromyxofibroma
D Chondrosarcoma
E Osteochondroma
D Chondrosarcoma
QUESTION 8
A 45-year-old man unde1went chemotherapy and limb-sparing surgery to treat a soft tissue sarcoma in his left leg. He remains under regular MRI surveillance to detect signs of recurrent disease. What features on MRI would be most suggestive of disease recurrence?
A New areas of high signal on proton density images
B New areas of high signal on Tlw images
C New areas of high signal on T2w images
D New areas of reduced signal on Tl w images
E New areas of reduced signal on T2w images
C New areas of high signal on T2w images
QUESTION 9
An aggressive, lytic bone lesion is observed to destroy the cortex of the second metacarpal in a 70-ycar-old woman. What is the most likely cause for these appearances?
A Metastatic breast cancer
B Metastatic colon cancer
C Metastatic lung cancer
D Metastatic renal cancer
E Metastatic thyroid cancer
C Metastatic lung cancer
Skeletal metastases tend to involve the axial rather than appendicular skeleton, reflecting their predilection for bones containing red marrow. Metastases from bronchial carcinoma account for half of all peripheral metastases.
QUESTION 11
A solitary, lytic lesion with aggressive features is an unexpected incidental finding on radiography of the left knee. Which radiological feature would favour a diagnosis of meastasis rather than primary bone tumour?
A Bone expansion
B Diaphyseal location
C Florid periosteal reaction
D Tumour bone formation
E Soft tissue mass
B Diaphyseal location
QUESTION 18
A 27-year-old man is referred by his GP with progressively painful swelling of his left knee following a minor football injury some weeks ago. The radiograph shows a 5-cm ill-defined lytic lesion within the left distal femoral metaphysis, with a permeative pattern of bone loss and areas of cloud-like ossification. There is an extensive periosteal reaction, predominantly orientated perpendicular to the cortex. What is the most likely diagnosis?
A Aneurysmal bone cyst
B Chondrosarcoma
C Ewing’s sarcoma
D Metastasis
E Osteosarcoma
E Osteosarcoma
The appearances are highly aggressive, and characteristic of osteosarcoma. The tumour matrix indicates a tumour of osseous rather than cartilaginous origin, malcing chondrosarcoma highly unlikely.
(Ped) QUESTION 19
A 5-year-old presents with a 2-month history of a painful right knee. On radiograph, there is a poorly defined lytic lesion in the distal femoral metaphysis, with an associated sunburst type periosteal reaction. An MRI is performed to classify this lesion further. Which one of the following imaging protocols would you choose?
A CT chest, abdomen and pelvis, with MRI Tlw and T2w axial and coronal sequences of the femur
B CT chest, with MRI Tlw and T2w axial, sagittal, coronal sequences of the femur
C Isotope bone scan, CT abdomen with MRI Tlw and T2w sagittal, coronal, axial sequences of the femur
D Isotope bone scan, CT chest with MRI Tlw and T2w sagittal, axial, coronal sequences of the femur
E MRI Tlw and T2w axial, sagittal and coronal sequences of the femur
D Isotope bone scan, CT chest with MRI Tlw and T2w sagittal, axial, coronal sequences of the femur
The typical imaging algorithm for children suspected of a primary bone malignancy includes plain radiograph, MRI to cover the entire bone involved by the lesion, bone scintigraphy to look for skeletal metastases and a CT chest for pulmonary metastases.
(Ped) QUESTION 28
A 13-year-old girl presents with a 3-month history of nonspecific neck ache with muscle spasm. A radiograph of her cervical spine reveals a 3-cm lucent lesion with a sclerotic rim in the posterior elements of C4. There is minimal periosteal reaction. Bone scintigraphy demonstrates a region of intense uptake correlating with the radiographic findings. On MRI, the lesion yields low signal on Tlw and medium to high signal on T2w sequences, as well as mild bone marrow oedema. Which one of the following is the most likely diagnosis?
A Aneurysmal bone cyst (ABC)
B Nonossifying fibroma (NOF)
C Osteoid osteoma
D Osteoblastoma
E Osteosarcoma
D Osteoblastoma
The differential diagnoses for a lesion within the posterior elements of a vertebral body include osteoid osteoma, osteoblastoma and an aneurysmal bone cyst.
QUESTION 33 A 13-year-old boy is referred to the orthopaedic surgeons with a short history of pain and swelling around his left elbow. The radiograph reveals a 4-cm area of permeative bone destruction within the distal diaphysis of the left humerus, with a wide zone of transition. There is an extensive associated soft tissue component and evidence of a ‘hair-on-end’ pattern of periosteal reaction. What is most likely diagnosis?
A Askin tumour
B Chondroblastoma
C Chondromyxoid fibroma
D Ewing’s sarcoma
E Malignant fibrous histiocytoma
D Ewing’s sarcoma
Infection and Langerhans cell histiocytosis (LCH) should be considered in the differential diagnosis of a permeative bone lesion in a child. Askin tumour is a rare primitive neuroectodermal rumour of the chest wall in children.
QUESTION 34 A 2-cm, well-defined lytic bone lesion in the proximal tibial metaphysis is an incidental finding in a 25-year-old woman. The lesion has a thic sclerotic margin and there is a ground glass appearance to the matrix.There is a history of endocrine disturbance and several cafe-au-lait spots are evident on examination. Skeletal scintigraphy subsequently reveals multiple areas of increased activity within the skeleton. What is the most likely diagnosis?
A Gardner’s syndrome
B Mazabraud’s syndrome
C Maffucci’s syndrome
D McCune-Albright
E Ollier’s syndrome
D McCune-Albright
McCune-Albright syndrome is characterised by polyostotic fibrous dysplasia, cafe-au-lait spots and endocrine disturbance (most commonly precocious puberty in girls). The rare association of polyostotic fibrous dysplasia and soft tissue mxyomas is Mazabraud’s syndrome.
QUESTION 36 An 80-year-old man undergoes skeletal scintigraphy for multifocal skeletal pain, malaise and weight loss. The scintigram shows diffusely increased activity throughout the skeleton, with absent renal activity. What is the most likely diagnosis?
A Metastatic bladder cancer
B Metastatic colon cancer
C Metastatic gastric cancer
D Metastatic lung cancer
E Metastatic prostate cancer
E Metastatic prostate cancer
QUESTION 38 A young patient is newly diagnosed with diaphyseal aclasis. What would be the expected imaging findings?
A Multiple enchondromas
B Multiple enostoses
C Multiple osteochondromas
D Multiple osteomas
E Multiple osteoid osteomas
C Multiple osteochondromas
QUESTION 41
A 15-year-old boy is noted to have a solitary lytic lesion expanding the cortex of the proximal tibia. An MRI demonstrates multiple fluid levels. What is the most likely diagnosis?
A Aneurysmal bone cyst
B Enchondroma
C Giant cell tumour
D Osteoblastoma
E Simple bone cyst
A Aneurysmal bone cyst
QUESTION 55
An incidental finding on plain film is a 2-cm lucency within the diaphysis of the right humerus, which exhibits chondroid calcification. Which clinical or radiological feature would favour a diagnosis of chondrosarcoma rather than enchondroma?
A Age less than 20 years
B Circular, curvilinear or nodular calcific densities
C Periosteal reaction
D Slow growth
E Well-defined round or elliptical margin
C Periosteal reaction
Outside the hands and feet, chondrosarcoma is five times more common than enchondroma.
QUESTION 57
A 20-year-old man complains of a 3-month history of pain from his lefr femur. The pain is of insidious onset and is worse at night. As part of his assessment, a bone scintigram is performed, which shows a corresponding area of abnormaliry in the left femoral shaft, characterised by a focus of very high activiry surrounded by a diffuse area of modestly increased activiry. What is the most likely diagnosis?
A Aneurysmal bone cyst
B Enostosis
C Enchondroma
D Osteoid osteoma
E Osteoma
D Osteoid osteoma
QUESTION 72
An 18-year-old man attends his general practitioner with a painful right knee. His radiograph shows a well-defined, lobular, lytic lesion within the proximal tibial epiphysis, extending into the metaphysis. There is a faintly sclerotic margin and no matrix calcification. What is the most likely diagnosis?
A Chondroblastoma
B Chondromyxoid flbroma
C Enchondroma
D Giant cell tumour
E Osteoid osteoma
A Chondroblastoma
QUESTION 80
A radiograph of the left knee of a 35-year-old man reveals a 3-cm lytic lesion sited eccentrically in the proximal tibia. It has a well-defined non-sclerotic margin, and extends to the tibial articular surface. What is the most likely diagnosis?
A Anemysmal bone cyst
B Chondroblastoma
C Giant cell tumour
D Non-ossifying flbroma
E Osteoid osteoma
C Giant cell tumour
