Case: multiple punched-out radiolucencies

Correct answer: B. "Punched out"

• A. A cotton-wool appearance — mixed radiopaque patches on a dense background — belongs to the late (osteoblastic) stage of Paget disease of bone.
• B. Correct. Multiple sharply defined radiolucencies that look as though they were stamped out of the bone, with no corticated rim, are the classic punched-out lesions of multiple myeloma.
• C. Soap-bubble multilocularity is described for ameloblastoma and odontogenic myxoma; those are expansile multilocular lesions, not scattered discrete holes.
• D. A salt-and-pepper trabecular pattern with loss of the lamina dura is seen in hyperparathyroidism.

Correct answer: C. Plasma cells

• A. Ghost cells are the histologic hallmark of the calcifying odontogenic cyst (Gorlin cyst), a single lesion, not multifocal lytic disease.
• B. Multinucleated giant cells characterise central giant cell granuloma and the brown tumour of hyperparathyroidism.
• C. Correct. Multiple myeloma is a malignant monoclonal proliferation of plasma cells in the marrow, producing a monoclonal immunoglobulin spike and lytic bone lesions.
• D. T-cell malignancies produce lymphomas and leukaemias, which do not give this punched-out radiographic pattern.

Correct answer: B. Multiple myeloma

• A. Langerhans cell histiocytosis also causes punched-out lesions and 'floating teeth', but it is a Langerhans (dendritic) cell disorder, not a plasma-cell one, and is far more common in children and young adults.
• B. Correct. Punched-out lytic lesions plus a plasma-cell proliferation is multiple myeloma. Bence Jones protein in urine and a serum M spike complete the picture.
• C. Hyperparathyroidism gives generalised demineralisation, loss of lamina dura, and brown tumours — a granular ground-glass or salt-and-pepper pattern rather than discrete punched-out holes.
• D. Paget disease produces enlargement of the jaw, hypercementosis, and a cotton-wool pattern, typically in older patients with a raised alkaline phosphatase.