Splenic involvement by blastic mantle cell lymphoma (large cell/anaplastic variant) mimicking splenic marginal zone lymphoma.

The most cases of splenic marginal zone lymphoma (SMZL) seem to respond favorably to splenectomy. The diagnosis of this lymphoma is mainly based on the recognition of a micronodular pattern of splenic involvement with marginal zone differentiation. However, it is possible to find so-called "marginal zone differentiation" in splenic involvement by other small B-cell lymphomas, particularly mantle cell lymphoma (MCL) and follicular lymphoma. We report a case of blastic MCL, large cell/anaplastic variant with a high level of clinical aggressiveness, showing biphasic cytology and a micronodular pattern which resembles SMZL. A single biopsy corresponding to this case shows two phases of tumoral progression in a MCL, a rare finding in MCL. In conclusion, the differential diagnosis of SMZL must take the possibility of a blastic MCL with biphasic cytology into account, as the case here. Copyright 1999 Wiley-Liss, Inc.