bone neoplasms Flashcards
bone tumours can be grouped into : primary vs metastatic tumours.
which is the most common malignant bone tumour?
Carcinoma
Among the primary malignant bone tumours, —– is the most common (35%), followed by —– (25%) and —– sarcoma
(16%*).
osteosarcoma > chondrosarcoma > Ewing
Osteosarcoma and Ewing sarcoma mostly affect —–
Chondrosarcoma mostly affect —–
children & young adults
older patients
Clinical presentation of primary malignant bone tumour
- Pain, mass & swelling of affected area, fracture and loss of function.
- 20-25% present with metastatic disease [ Lungs (38%) / Bone (31%) / Bone Marrow (11%) ]
- might have constitutional symptoms – fever / anemia / weight loss
Common investigations used for bone tumours
- Xray – IMPT 1st line
- MRI (or CT)
- Bone radionuclide bone scan – detect tumour spread to other bones
- Positron emission tomography (PET) scan – highly sensitive to scan whole body for tumour spread
- Biopsy (needle / incisional surgical) – gold standard in diagnosing
Prognostic factors for primary malignant bone tumours
- Size of tumours (T1 better prognosis than T2. > 8cm or < 8cm).
- Histopathological grading.
- Location of the tumours and margin clearance: Good local control (anatomically resectable limbs) versus poor local control (spine and pelvis).
- Stage: metastatic disease has worse prognosis.
- Response to chemotherapy (good > 90% necrosis) only for osteosarcoma (and Ewing sarcoma).
Location of bone tumour -> What tumour
- Epiphysis : Chondroblastoma
- Metaphysis (of long bones) : Osteosarcoma
- Epiphyseal-metaphyseal region : Giant cell tumour
Definition of osteosarcoma
A mostly high-grade malignant bone tumor that produces osteoid directly from tumor cells.
Risk factors of osteosarcoma
- Male
- Younger (10-25 y/o)
- Older patient often a/w precursor lesion = Paget’s disease
X-ray of osteosarcoma
- large, destructive, lytic or blastic mass
- Permeative margins;
- may break through cortex and elevate periosteum;
- sunburst pattern due to new bone formation in soft tissue
Histology of osteosarcoma
A lace-like pattern of OSTEOID is produced by eosinophilic matrix entrapping anaplastic tumor cells.
Definition of chondrosarcoma
Malignant bone tumour that produces cartilage (but not osteoid).
Risk factors of chondrosarcoma
- male
- older (30-60 y/o)
- a/w pre-existing bone tumour (enchondroma or osteochondroma)
Characteristics of chondrosarcoma
Often large painful tumors of long bones or ribs that grow rapidly during adolescence and reach 8 cm or larger
NOT chemo sensitive
Gross appearance of chondrosarcoma
- Large lobulated tumour with pearly white or light blue, often with focal calcification.
- Myxoid change is more common and suggestive of malignancy.
- Areas of hemorrhagic necrosis may be present.
Histology of chondrosarcoma
- Cartilaginous matrix
- Permeation of bone trabeculae
- Soft tissue & marrow invasion
Osteochondroma / exostosis
- Most common benign bone tumours arising in the long bones.
- A benign cartilage-capped tumor that is attached to the underlying skeleton by a bony stalk.
- Solitary (85%). Remaining cases multiple hereditary exostoses syndrome (EXT1 and EXT 2 genes).
- Bone extension containing cortex and periosteum covered by a thin cartilaginous cap.
- Rarely undergoes malignant transformation (chondrosarcoma).
What is giant cell tumour
- Most common and important of all the giant cell rich neoplasms of the skeleton.
- Benign but locally aggressive neoplasm with high rate of recurrence (up to 30%).
- Usually solitary
- Long tubular bones (usually knee)
- In epiphyseal-metaphyseal region
Risk factors of giant cell tumour
- 30-50 y/o
- females
- more common in oriental countries
Histology of giant cell tumours
- Abundant giant cells often with numerous nuclei (50 to 100 per cell).
- Stromal cells similar to giant cells.
- No osteoid formation.
- Extremely rare malignant transformation.
What’s fibrous dysplasia
- benign tumor reflecting a localized developmental arrest
- All of the components of normal bone are present, but they do not differentiate into mature structures.
- result from a somatic gain-of-function mutation in GNAS1.
GROSS
* tissue is tan-white & gritty
* curvilinear shapes of trabeculae mimic Chinese characters
* bone lacks prominent osteoblastic rimming
