The panoramic radiograph shows multiple sharply demarcated round radiolucencies without a corticated border. Which cell type is involved in the underlying medical condition?

Correct answer: B. Plasma cells

• A. 'Round cells' is a non-specific descriptor sometimes applied to lymphomas or small blue round-cell tumors but is not the specific cell of multiple myeloma.
• B. CORRECT — Multiple myeloma is a malignant monoclonal proliferation of PLASMA CELLS in the bone marrow. It produces the punched-out radiolucencies shown, along with bone pain, anemia, hypercalcemia, and renal failure (CRAB features). Bence-Jones proteins may be found in urine.
• C. T cells are involved in T-cell lymphomas, not multiple myeloma. T-cell disorders don't typically produce punched-out osteolytic lesions.
• D. Ghost cells are found in calcifying odontogenic (Gorlin) cysts and craniopharyngiomas — not myeloma.