Pathology Cheat Sheet
Read Bone As a Tissue
Bone pathology for NEET-PG: osteomyelitis sequestrum and involucrum, osteosarcoma Codman triangle, Ewing sarcoma t(11;22), GCT, and bone metastases here.
MedNext Academy | 3 min read
Read Bone As a Tissue
Bone pathology for NEET-PG: osteomyelitis sequestrum and involucrum, osteosarcoma Codman triangle, Ewing sarcoma t(11;22), GCT, and bone metastases here.
The pathology of osteomyelitis and the classification of primary bone tumours.
High-yield lines
- Osteomyelitis is infection of bone most commonly caused by Staphylococcus aureus.
- A sequestrum is dead necrotic bone, and an involucrum is new reactive bone surrounding it.
- Tuberculous osteomyelitis of the spine is called Pott disease.
- Osteoid osteoma is a small painful benign tumour relieved by aspirin.
- Giant cell tumour of bone is a locally aggressive lesion at the epiphysis of long bones with a soap-bubble appearance.
- Osteosarcoma is the most common primary malignant bone tumour and arises at the metaphysis around the knee in adolescents.
- Osteosarcoma produces malignant osteoid and shows a Codman triangle and sunburst pattern on imaging.
- Osteosarcoma is associated with retinoblastoma gene mutation and prior radiation.
- Ewing sarcoma is a small round blue cell tumour of the diaphysis with an onion-skin periosteal reaction and t(11;22).
- Chondrosarcoma is a malignant cartilage tumour occurring in older adults in the axial skeleton.
- Enchondroma is a benign cartilage tumour of the small bones of the hands.
- The most common malignant tumour of bone overall is metastasis, especially from breast, prostate, and lung.
Mapped competency codes
- PA33.1
- PA33.2
Continue into the full chapter
This summary maps to PA33-bone-and-soft-tissue.
Frequently Asked Questions
What is a sequestrum in osteomyelitis?
A fragment of dead necrotic bone separated from living bone, often surrounded by a shell of new reactive bone called an involucrum.
What are the features of osteosarcoma?
A malignant bone tumour at the metaphysis around the knee in adolescents that produces malignant osteoid and shows a Codman triangle and sunburst pattern.
What distinguishes Ewing sarcoma?
A diaphyseal small round blue cell tumour with an onion-skin periosteal reaction and the t(11;22) EWS-FLI1 translocation.
What is the most common malignant tumour of bone?
Metastatic carcinoma, most often from breast, prostate, lung, kidney, and thyroid, exceeding primary bone malignancies in frequency.
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