Cutaneous involvement in the lymphoepithelioid variant of peripheral T‐cell lymphoma, unspecified (Lennert lymphoma). Report of a case and review of the literature

Lennert lymphoma (LL), or the lymphoepithelioid variant of peripheral T-cell lymphoma, is an uncommon entity with rarely seen or reported presentations in the skin. Cutaneous involvement of LL has been characterized by asymptomatic, non-ulcerated, red to violet papules, nodules and small plaques (less than 5 cm) on the trunk and extremities. Histologically, there are localized cellular lymphoid infiltrates in the dermis that tend to localize around blood vessels or skin appendages. Key to the diagnosis of LL is the presence of epithelioid histiocytes and atypical small lymphoid cells without increased vascularity or epidermotropism. Immunophenotyping shows a dense monoclonal T-cell population commonly associated with aberrant loss of T-cell-associated antigens. T-cell receptor gene rearrangements are also identified. Patients typically present with advanced stage and have a low 5-year survival. Herein, we present a case of cutaneous involvement by LL at the time of initial presentation that persisted after initiation of chemotherapy and was finally verified as secondary cutaneous involvement of LL 1 year later histologically, immunophenotypically and by T-cell receptor gene rearrangement studies.