PTH-02-Disease of Soft Tisssue

Question 1

Diagnosis Main Point

Answer 1

Age, History, site, duration, pain, x-ray, CT, MRI, clinical-radiological-pathology

Question 2

Common sites of primary cancers that metastasize to bone

Answer 2

Prostate, 
Breast, 
Thyroid,
Kidney, 
Lung, 
GIT

Question 3

Secondary tumor may radiologically be

Answer 3

osteoblastic (prostate, breast),
osteolytic (kidney, lung and melanoma )
mixed.

Question 4

Common Cancer in Children

Answer 4

Neuroblastoma,
Nephroblastoma
Ewing’s sarcoma….etc

Question 5

Sites involved by metastasis:

Answer 5

axial skeleton(vertebral column, pelvis, ribs, skull, sternum),
proximal femur
Humerus.

Question 6

Primary Bone Tumors

Answer 6

Benign OR malignant
-Bone forming.
-Cartilage forming.
-Miscellaneous :fibrous, hematopoitic, multiple myeloma…. etc
Multiple myeloma is the most common in middle age
Osteosarcoma is the most common malignant tumor in children/ adolescents

Question 7

Bone Forming Tumors

Answer 7

BENIGN
1- Osteoma :
2- Osteoid Osteoma/Osteoblastoma
MALIGNANT
3- Osteosarcoma

Question 8

Osteoma

Answer 8

Mainly affects frontal bones.
May affect all ages, mainly 40-50 years.
Asymptomatic, may produce pressure symptoms , or sinus obstruction.
Histologically: composed of mature bone.
May be left without treatment or removed
- Cause pressure symptoms.
- Cosmetic reason.

Question 9

Osteoid Osteoma/Osteoblastoma

Answer 9

O.Osteoma in proximal femur <1.5- 2cm.
Age teenage & twenties, M:F is 2:1
Typical symptom : localized pain , worse at night, unrelieved by aspirin
X-ray: well defined cortical tumor with well defined radiolucent central nidus.
Simple OSTEOMA occurs in bones of skull
Histology: Trabeculae of woven bone surrounded by osteoblasts with central vascularized nidus.

Question 10

Osteoid Osteoma vs Osteoblastoma

Answer 10

Osteoblastoma is similar, but more than 1.5-2cm. in size, more in axial skeleton
Slowly, progressing & increasing in size
AGGRESSIVE OSTEOBLASTOMA
Important to differentiate from Osteosarcoma

Question 11

Osteosarcoma

Answer 11

Malignant mesenchymal neoplasm, in which the neoplastic cells produce OSTEOID
Most common malignant primary, non hematopoitic, bone tumor.
M>F, 75% < 20 years old
Majority in metaphyses of long bones, most around the knee
May be multiple in children with p53 mutation

Question 12

Osteosarcoma-cause

Answer 12

Primary, arising de novo     OR
Secondary to an underlying bone disease e.g. Paget’s disease, radiation
-Most are intramedullary→ cortex →peri- osteum → soft tissue
-Rarely extends into joints
-Location :
--Classical ( Intramedullary)
--Paraosteal (Juxtacortical)
--Periosteal

Question 13

Osteosarcoma-Pathogenesis

Answer 13

Genetic mutations:
-RB gene mutation on chromosome 13 in 60-70% of sporadic cases 
-Inherited in familial retinoblastoma
-Other mutations: p53, cyclins,CDK’s…etc
Predisposing conditions

Question 14

Osteosarcoma-Clinical Features

Answer 14

Enlarging mass, with or without pain.
Sometimes pathological fracture.
Hematogenous metastasis is common, mostly to the lungs.
X-ray: Ill-defined lesion, cortical destruction & extension to the marrow or soft tissue. ( Lytic/Sclerotic)
Codman’s triangle is a radiological term due to periosteal reaction with new bone formation.

Question 15

Osteosarcoma-Pathology

Answer 15

Pleomorphic large malignant cells, prominent mitoses
Lace like osteoid formed directly by malignant cells.
Numerous osteoclasts may be seen
Histological Variants :
-Predominantly osseous.
-Chondroblastic
-Fibroblastic 
-Telengiectatic ………………. Others

Question 16

Osteosarcoma-Treatment

Answer 16

Chemotherapy→ Assess amount of NECROSIS
Surgery
Radiation

Question 17

Osteosarcoma-Prognosis

Answer 17

Aggressive tumor
The prognosis depends on the stage & variant of the tumor (conventional or other variants), location……etc
The grade is not as important as stage in osteosarcoma.

Question 18

Primary Cartilage Forming Tumors

Answer 18

Benign
-Osteosarcoma
-chondroma
Malignant
-Chondrosarcoma
Miscellaneous
-Giant cell tumor(benign)
-Ewing tumor(malignant)

Question 19

Chondroma

Answer 19

Benign tumor composed of mature hyaline cartilage; 10% of primary bone tumor.
Intracortical (enchondroma) or extracortical.
Any age can be affected ( 20-40 y)
Small bones of hands and feet, solitary or multiple
Usually presents as asymptomatic bone swelling.

Question 20

Chondroma & Enchondroma

Answer 20

Solitary benign.
Multiple→chondrosarcoma in 1/3
-Ollier’s disease: multiple enchondromas with endocrine abnormalities.
-Maffucci’s syndrome: Multiple chondromas with multiple hemangiomas.
Morphology : well circumscribed mass of mature cartilage

Question 21

Osteochondroma (exostosis)

Answer 21

Single or inherited multiple
Arise from the metaphysis near growth plate of long tubular bones 1- 20cm
Majority around knee
Composed of outgrowth of cartilage cap overlying bone & bone marrow
May become ossified
Very rare malignant transformation

Question 22

Chondrosarcoma

Answer 22

Malignant tumors of mesenchymal cells that produce cartilagenous matrix.
Older patients, 40-60y, M>F.
Site: central skeleton (pelvis,shoulder, ribs)
Primary (arise de novo), majority.
Secondary: multiple enchondromas or rarely osteochondromas.

Question 23

Chondrosarcoma

Answer 23

Grossly: Glistening mass in the medullary cavity.
Histology: Chondroid cells with variable pleomorphism & binucleation. No osteoid.
Prognosis: depends on grade
Most are low grade, & recurrence
10% dedifferentiated & metastasize to lung ….etc

Question 24

Fibrous Cortical Defect/ Non Ossifying Fibroma

Answer 24

Often symptomless

• Probably developmental, may mature
• Children
• Benign fibroblast proliferation

Question 25

Fibrous Dysplasia

Answer 25

• Failure of normal bone elements to differentiate into mature bone.
• Monostotic & Polyostotic
• -Localized intramedullary fibrous lesion with curved woven bone ’Chinese letters’
• -No osteoblast rim

Question 26

Miscellaneous Tumors

Answer 26

1- Giant Cell Tumor (Osteoclastoma)

2- Ewing Sarcoma

Question 27

Giant Cell Tumor (Osteoclastoma)

Answer 27

Bulky tumor at the end of long bones
Age: Mostly 20-40 years, F>M
Sites: Epiphysis of long bones; femur, tibia, radius, extends into joint
Most of them are solitary.
Histology: 2 population of cells:
-Multinucleated osteoclast like giant cells
-Background mononuclear stromal cells are neoplastic

Question 28

GCT- Differential diagnosis

Answer 28

-Aneurysmal bone cyst.
-Brown tumor of hyperparathyroidism
-Osteosarcoma with giant cells.
-Many, many others !
All contain GIANT CELLS !
Clinical correlation & X ray is a must!!

Question 29

Ewing Sarcoma

Answer 29

Primitive Neuro-Ectodermal Tumor (PNET) undifferentiated round cells arising within the marrow cavity: Small Blue Cell Tumor
M>F ,most occur in teenagers ( 5-20)
Classic translocation t(11;22)
X-ray: Lytic medullary lesion with concentric ‘onion skin’ layering of new periosteal bone.

Question 30

ES-Morphology

Answer 30

Gross: often affects the diaphyses of long bones, pelvis and tibia with necrosis & hemorrhage
Micro: sheets of undifferentiated small round blue cells , PAS positive material in cytoplasm consistent with glycogen
Tumoral cells destroy cortex and periosteum and invade surrounding tissues.

Question 31

ES-CP, TT, PN

Answer 31

Clinical features: 
Mass, pain with local inflammation
Treatment : 
Chemotherapy, surgery and/ or radiation
Prognosis: 
5 year survival rate of 75%