Multiple myeloma and cutaneous anaplastic large T-cell lymphoma in the same patient: is there a causal relation?

Synchronous occurrence of lymphomatous proliferations of B and T lineage in the same patient is a very rare event and still poorly understood. All the cases reported in the English language literature are described as single case reports. We report a case of 49-year-old man, with 2-year history of multiple myeloma, presented with a raised, erythematous and ulcerated nodule in the anterior aspect of his right thigh. Histologic examination of biopsy specimen showed a dense dermic infiltrate made of large balastic cells displaying anaplastic morphology with no epidermotropism. Immunohistochemical study showed that tumor cells stained positive with CD30, EMA and CD4, and negative for CD3, CD8, CD5, CD20, CD79a, CD138 and anaplastic lymphoma kinase 1 (ALK or Ki-1).