Synchronous Follicular Lymphoma, Kaposi Sarcoma, and Castleman's Disease in a HIV-Negative Patient With EBV and HHV-8 Coinfection

The authors describe the case of a 65-year-old woman who was HIV negative and had a lymph node biopsy that showed concurrent follicular lymphoma (FL; grade 3A), Kaposi sarcoma (KS), and Castleman's disease (CD) with coinfection by human herpes virus-8 (HHV-8) and Epstein-Barr virus (EBV). The lymphoma was positive for CD20, CD10, and BCL6 and negative for BCL2. Flow cytometry showed a clonal lambda B-cell population, and polymerase chain reaction (PCR) showed a clonal immunoglobulin heavy chain gene rearrangement, confirming a neoplastic B-cell process. Focally, the FL component showed numerous EBER1-positive cells, with rare HHV-8-positive cells. The KS component showed strong HHV-8 expression with rare EBER1-positive cells. The CD component showed scattered HHV-8, viral interleukin-6, and EBER1-positive cells. The simultaneous occurrence of a FL, KS, and CD in an HIV-negative patient expands the spectrum of HHV-8-positive neoplasms and suggests the possibility of HHV-8 rendering mature B-cells hyperresponsive to antigenic stimulation, providing an expanded target for second site mutations or cytokine-driven hyperplasia, culminating in lymphoma.