Cyclin D1 as an aid in the diagnosis of mantle cell lymphoma in skin biopsies: a case report.

Mantle cell lymphoma (MCL), an uncommon and aggressive form of non-Hodgkin lymphoma, typically involves lymph nodes. It usually only secondarily involves extranodal sites. We describe an unusual case of a MCL that presented and relapsed in the earlobes. Light microscopic findings were initially regarded as suggestive of small lymphocytic lymphoma, although subsequent analysis of fresh tissue by flow cytometry led to the diagnosis of MCL. Retrospective application of a broad panel of recently developed markers suitable for analysis of routinely processed tissue yielded results that also permitted a diagnosis of MCL. If these results had been available at the time of initial presentation, they would have obviated the need for rebiopsy. Greater awareness not only of the phenotypic criteria by which lymphomas are classified but of the lymphoma markers available for evaluation of routinely processed tissue should facilitate the accurate diagnosis of diseases like MCL and minimize the risk of misdiagnosis as an indolent disorder.