Mantle Cell Lymphoma Presenting as a Subcutaneous Mass of the Right Leg.

Mantle cell lymphoma (MCL) is a relatively rare B-cell non-Hodgkin lymphoma, typically presenting with extensive lymphadenopathy, bone marrow involvement, and splenomegaly. Extranodal sites can also be involved. We discuss a 73-year-old man whose MCL presented with a 6-month history of a subdermal mass of the right upper thigh and no systemic symptoms.