Extracavitary primary effusion lymphoma presenting as a solitary brain mass.

ABSTRACT

Primary effusion lymphoma (PEL) is an uncommon B-cell lymphoma associated with human herpesvirus 8 and comprises 3-4% of all HIV-related lymphomas. It traditionally presents as a pleural, pericardial, and/or peritoneal effusion, though it can occasionally manifest as an extracavitary or solid mass in the absence of an effusion. The extracavitary or solid variant of primary effusion lymphoma has been reported in the skin, gastrointestinal tract, lung, and lymph nodes. However, very few cases have been reported in the central nervous system. We describe a case of extracavitary or solid variant of primary effusion lymphoma presenting as a brain mass in an HIV-positive man, highlighting the clinicopathologic and immunophenotypic findings of a rare entity.

Primary effusion lymphoma (PEL) is an uncommon and aggressive form of large B-cell lymphoma with a grim outlook, making up less than 1% of all lymphomas. PEL is linked to human herpesvirus 8 and predominantly impacts individuals with HIV or weakened immune systems. The typical presentation of PEL involves cancerous fluid accumulating in the chest or abdominal cavities. Occasionally, PEL can appear as a solid mass outside these cavities, termed extracavitary PEL (EC-PEL). The case we are describing highlights the difficulties in diagnosing PEL/EC-PEL. It is crucial for healthcare providers to consider EC-PEL when dealing with human herpesvirus 8-positive B-cell lymphomas, especially when patients have weakened immune systems and an unusual clinical scenario involving a solid mass, as seen in this case.