Kaposi sarcoma-associated herpesvirus/human herpesvirus 8-associated extracavitary primary effusion lymphoma presenting as multiple lymphomatous polyposis.

Primary effusion lymphoma (PEL) is a distinct clinicopathological entity usually characterized by presentation as a lymphomatous body cavity effusion in the absence of solid tumor mass or dissemination during its clinical course. PEL can also rarely occur as a solid lymphoma involving nodal and extranodal sites and is referred to as extracavitary PEL. Here we report a unique case of extracavitary PEL in a 49-year-old HIV-seropositive patient who presented with vague abdominal pain and 20-lb weight loss. Esophagogastroduodenoscopy and colonoscopy revealed more than 100 broad-based intestinal polyps ranging from 2 mm to 3 cm in size, spreading from the duodenum to the rectum as a typical impression of "intestinal polyposis syndrome." Multiple biopsies demonstrated sheets of large lymphoid cells with characteristic features of extracavitary PEL with strong Kaposi sarcoma-associated herpesvirus/human herpesvirus 8 virus positivity by immunohistochemistry. Extracavitary PEL presenting as distinctive multiple lymphomatous polyposis as manifested in the case has not been described previously.