MCQs-pathology 1
– Chondroblastoma – treat with interlesional curretage and bone graft.

– tumors with lymph node mets: synovial sarcoma, epitheliod sarcoma, leiomyosarcoma, and rhabdomyosarcoma

– most common primary benign tumour of bone: osteochondroma

– young woman with neck pain – lytic lesion of body and pedicle of C4; increased uptake on bone scan locally and in the kidney; dx: metastatic thyroid cancer – Rx with radiation and chemo

– look for diffuse osteoporosis with multiple myeloma

– what is the best test for multiple myeloma – bone marrow aspirate. ?Supposedly better than serum electrophoresis

– myositis ossificans is distinguished from osteosarcoma by the peripheral pattern of calcification in MO

– myositis ossificans: burns, DISH, hypertrophic osteo, ank spond, post-trauma, prolonged immobilization

– for most soft tissue sarcomas – add radiation after the wide resection

– for a chondrosarcoma of the popliteal fossa – probably would add XRT postop; even though chondrosarcomas are highly radioresistant, using it as an adjuvant when the tumour is very difficult to resect and cells may remain in the bed is probably not a bad idea (esp in the pelvis).

– Pagets can transform into osteosarc, chondrosarc, MFH, fibrosarc

– rate of recurrence after excising soft tissue sarcoma – related most to adequacy of excision

– cell anaplasia is a bad prognostic sign in all tumours – indicates aggressiveness

– indications that an osteochondroma has undergone sarcomatous degeneration:
– cartilage cap > 2 cm
– pain and increase in size
– increase in calcificaction
– soft tissue mass

– remember that Paget’s disease often has an increase in alk phos and urine hydroxyproline. Unless immobilized, their calcium is normal, and expect their phosphate to be normal too. Acid phosphatase also normal. Many questions come up about spinal stenosis from vertebral involvement of Pagets – you have to recognize based on the biomechanical profile that this is Paget’s and not some osteosarcoma.

– fibrous dysplasia almost NEVER has a periosteal reaction

– xanthoid foam cells are found in NONOSSIFYING FIBROMAS

– hyperparathyroidism and Brown’s tumours can look much like giant cell tumours histologically – get the bloodwork to show the increased Ca, decreased phosphate.

– periarticular new bone formation is consistent with Charcot joints.

– synovial response to chronic inflam: lymphoid nodules and accumulation of lymphocytes

– leukemia in children localizes to areas of rapid growth of long bones – metaphyseal/diaphyseal

– bisphosphonates inhibit mineralization of osteoid – not useful in preventing HO (take them off it and the osteoid will mineralize)

– Caffey’s disease is infantile cortical hyperostosis – it is not an osteochondroses

– Pathology of Ewing’s: uniform nuclei with small, unprominent nucleoli, finely dispersed and lacy chromatin.

– “Rosettes” are seen in NEUROBLASTOMA
– “Pseudo-Rosettes” are seen in Ewing’s

– osteoid osteomas – have severe night pain, have tiny nerves in the nidus, with closely situated osteoid; often are DIAPHYSEAL.

– renal cell mets – embolize then take out – curative in some.

– PVNS – greater than 15% recurrence rate with excision

– acro-osteolysis is seen with SCLERODERMA

– the sunburst effect of osteosarcomas is related to the aggressive growth right through cortical bone

– osteoporosis and corticosteroids: the primary effect of steroids is GI mediated in a Vitamin D independent mechanism – they alter GI villus height and crypt depth and thus DECREASE GUT ABSORPTION OF CALCIUM

– osteosarcoma, metastatic carcinoma, Paget’s – all show woven bone; osteoporosis doesn’t .

– when you see lytic lesions on BOTH SIDES OF THE JOINT SURFACE – think PVNS.

– best confirmatory tests for early Paget’s – urine hydroxyproline. If the disease is early, it is in the osteolytic phase, where collagen is being broken down. In the reparative phase, the alk phos level increases, reflecting bony

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