Rare Cutaneous Primary Presentation of Extracavitary Primary Effusion Lymphoma.

Primary effusion lymphoma (PEL) is a rare and aggressive B-cell lymphoma typically associated with human herpesvirus 8 (HHV-8) and Epstein-Barr virus infections. It classically presents as a malignant effusion in body cavities, but rarely presents with an extracavitary variant characterized by solid tumors in lymph nodes or extranodal sites such as the gastrointestinal tract, skin, lungs, and nervous system. This case report describes an unusual presentation of primary cutaneous extracavitary PEL in an HIV-positive patient that has only been reported in 8 cases previously. The patient presented with a skin nodule in the right supraclavicular area. Histopathologic examination showed a malignant infiltrate in the dermis composed of sheets of plasmablasts. The immunophenotype of the cells shows the characteristic coinfection with HHV-8 and Epstein-Barr virus. The case presented herein contributes to expand the reported literature on primary cutaneous extracavitary PEL and performs a comprehensive review of this entity, which most dermatopathologists are unfamiliar with.