L2 Flashcards
(16 cards)
Osteoid osteoma
- Teenage (M 2:1 F), proximal femur, < 1.5-2cm, localized pain worse at night, relieved by aspirin
- X-ray findings: well defined cortical metaphyseal defect + radiolucent central nidus (vascularized that give PG)
- Histology: Interlacing trabeculae of woven bone surrounded by osteoblasts with central vascularized nidus
Simple osteoma occurs in bones of skull of adults (hard bone unlike osteoid osteoma)
Multiple Osteomas in Gardner syndrome “APC or B-catenin” (can also develop desmoid fibromatosis)
Osteoblastoma
more in axial skeleton, >2cm in size, pain less localized & don’t respond to aspirin well
Chondroma & Enchondroma Mutation Morphology Age Sites
- Benign solitary, if multiple [Ollier D. & Maffucci S. > IDH point mutation, risk of sarcoma in 1\3]
- Morphology: well-circumscribed mass of mature cartilage, Not infiltrative.
- Age: 20-40
- Sites: Small bones of hands, feet, long bones, pelvis
- Intramedullary (Enchondroma) or bone surface (juxtacortical chondroma)
Osteochondroma Mutation Histology Site Size
[exostosis]
• Single or inherited multiple, can be 1-20cm
• Sites: metaphysis near growth plate of long tubular bones [majority around knee, rare mandible]
• Histology: cartilage cap overlying bone & bone marrow (continuous), may become ossified
• Mutations: Inactivating mutation of EXT1 or EXT2
• Very rare malignant transformation (<2%, unless MHE up to 10%)
• Multiple hereditary exostosis (MHE) or thick cartilage cap (>2-3cm)
Fibrous Dysplasia
Mutation
Special feature ♥️
o Failure of normal bone to differentiate into mature bone [70% Monostotic, 30% Polyostotic]
o Pathology: Localized intramedullary fibrous lesion with curved woven bone ’Chinese letters,
No osteoblast rimming.
o Mutations:GNAS-1mutation,McCune-Albright Syndrome(3% of polyostotic)
Chondrosarcoma
Site
Grossly
Histology
[malignant]
• Malignant tumor of mesenchymal cells that produce cartilaginous matrix. 40-60yrs, M>F
• Site: axial skeleton, proximal Femur, very rare in extremity
• Primary [de novo], Secondary (from multiple enchondromas or osteochondromas)
• Morphology:
- Grossly: Glistening mass in medullary cavity,
- Histology: Chondrocytes with variable pleomorphism & binucleation, no osteoidmatrix
Giant cell Tumor (osteoclastoma)
Age
Site
Bulky tumor at the end of long bones
Age: Mostly 20-40 years f>m
Sites: Epiphysis of long bones; femur, tibia, radius
Majority are solitary
Giant cell Tumor (osteoclastoma)
Histology: 2 populations of cells:
Multinucleated large osteoclasts and giant cells
Mononuclear stromal cells are neoplastic
Differential diagnosis of Giant cell Tumor (osteoclastoma)
Aneurysmal bone cyst.
Brown tumor of hyperparathyroidism
Osteosarcoma with giant cells
Many others
How can we treat Giant cell Tumor (osteoclastoma)
Treated by surgical curettage or resection
Clinical behavior: unpredictable of Giant cell Tumor (osteoclastoma)
Most tumors are benign May be aggressive Recurrence may occur May ‘metastasize’ to lung Sarcomatous transformation may occur
Ewing Sarcoma & PNET Age Sex Classic translocation Some definitions
Primitive Neuro-Ectodermal Tumor (PNET)
Undifferentiated round cells arising within the marrow cavity
Small Round Blue Cell Tumor
M>F, most in children & teenagers (5-20)
Classic translocation: t(11;22) involving EWS gene
X-ray Ewing Sarcoma & PNET
Lytic medullary lesion
Concentric (onion skin) layering of new periosteal bone
Ewing Sarcoma & PNET
Clinical features
Treatment
Prognosis
Clinical features: Mass, pain with local inflammation
Treatment: chemotherapy, surgery +/- irradiation
Prognosis: 5 year survival rate of 75% for localized tumors
Ewing Sarcoma & PNET
Diaphyses of long bones, pelvis and tibia with necrosis & hemorrhage
PAS positive material in cytoplasm consistent with glycogen
Homer-Wright rosettes –neural differentiation
Tumoral cells destroy cortex and differentiation
Secondary tumors may radiologically be:
a- Osteoblastic (prostate, breast)
b- Osteolytic (kidney, lung and melanoma)
c- mixed
