Kaposi sarcoma herpesvirus/human herpesvirus 8-positive diffuse large B-cell lymphoma characterized by malignant ascites: A case report.

Herein, we report a rare case of Kaposi sarcoma herpesvirus/human herpesvirus 8 (KSHV/HHV8)-positive diffuse large B-cell lymphoma (DLBCL), which is characterized by malignant ascites and complex karyotypes. A 72-year-old male patient who tested negative for human immunodeficiency virus presented with thrombocytopenia and lymphadenopathies. He was diagnosed with KSHV/HHV8-associated multicentric Castleman disease (MCD). After three years, he developed progressive lymphadenopathies and massive ascites. The lymphoma cells in the ascitic fluid presented with characteristic immunophenotype and monoclonality, which support the diagnosis of KSHV/HHV8-positive DLBCL. Lymphadenopathies and massive splenomegaly are common manifestations of KSHV/HHV8-positive DLBCL. Nevertheless, peritoneal involvement, as observed in this case, is a rare presentation. This emphasizes the diagnostic complexities of KSHV/HHV8-associated lymphoproliferative disorders. Within the context of preexisting KSHV/HHV8-associated multicentric Castleman disease, the differential diagnosis of this disorder can be challenging.