Primary effusion lymphoma (PEL) is a rare type of B-cell non-Hodgkin lymphoma (NHL), which predominantly occurs in HIV-infected individuals, and is pathogenetically linked with Kaposi sarcoma (KS)-associated herpes virus/human herpes virus-8 (KSHV/HHV-8) infection with or without evidence of Epstein-Barr virus (EBV) co-infection. Although uncommon, PELs have been reported in immunocompetent patients and recipients of solid organ allografts. Rare cases of KSHV(-) EBV(+) post-transplant effusion lymphomas resembling PEL have also been described, as have KSHV(-) EBV(-) effusion lymphomas, the latter including those arising in individuals with chronic liver disease. We report a unique KSHV(-) EBV(-) post-transplant effusion lymphoma associated with serum paraproteins, occurring in an HIV(-) individual, which had cytologic features and phenotype similar to PEL, and displayed a complex karyotype including isochromosome 12p and translocation t(8;22), resulting in rearrangement of c-MYC.