A 22-year-old man presents with a dull ache and a firm swelling over the front of the middle third of the left leg present for two years. X-ray shows an eccentric mixed lytic and sclerotic lesion arising in the anterior cortex of the tibial diaphysis with multiple small radiolucent areas. Biopsy shows nests and cords of epithelial cells embedded in a fibro-osseous stroma resembling osteofibrous dysplasia. The diagnosis is:
- A Osteofibrous dysplasia
- B Ewing sarcoma
- C Adamantinoma ✓
- D Periosteal osteosarcoma
Correct answer: C. Adamantinoma
Explanation
Adamantinoma is a rare low-grade malignant biphasic tumour almost always located in the anterior cortex of the tibial diaphysis, showing epithelial nests within a fibro-osseous stroma. Its slow growth over years and the cortically based mixed lytic-sclerotic tibial lesion in a young adult are characteristic. Osteofibrous dysplasia shares the site but lacks the epithelial component, which is what separates the two entities histologically.
Reference: Bailey and Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.