Accumulation of bone-seeking agent in a patient with mediastinal seminoma.

A 39-year-old man presented with substernal pain and shortness of breath. Bone scan revealed a large soft-tissue uptake in anterior chest. Subsequent computed tomography showed a large mass lesion with well demarcated margins in anterior mediastinum. Percutaneous core needle biopsy and histopathologic examination diagnosed the mediastinal seminoma. Bone scintigraphy could delineate a wide spectrum of nonosseous disorders. The recognition of extraskeletal uptake of bone-seeking agent can enhance the diagnostic value of bone scintigraphy.