Extracavitary Primary Effusion Lymphoma Affecting the Oral Cavity: A Rare Case Report.

Primary effusion lymphoma (PEL) is an aggressive neoplasm often diagnosed in immunosuppressed patients demonstrating peritoneal, pleural, or pericardial effusions. This high-grade lymphoma is strongly associated with human herpesvirus 8 (HHV8) infection and most of the lesions also show the presence of Epstein-Barr virus in tumor cells, which lacks CD20 expression and reveals a plasmablastic morphology and phenotype. The extracavitary or solid variant of PEL is even rarer and usually affects the lymph nodes and is currently considered a clinical manifestation of the classic PEL. In the oral cavity, extracavitary PEL is extremely rare and only a few patients have been previously reported, with no detailed clinicopathological description. The recognition of oral extracavitary PEL is even more important given the occurrence of plasmablastic lymphoma in the oral mucosa, which shares many clinical, microscopic, and phenotypic features with PEL, therefore, demanding from pathologists the search for HHV8, especially in immunosuppressed patients, and an appropriate clinical evaluation. In this report, we aim to describe a very rare extracavitary PEL affecting the palate of a 36-year-old patient and to review the literature regarding the extracavitary presentation of this aggressive lymphoma. This report demonstrates the importance of searching for HHV8 infection in oral lymphomas with plasmablastic features.