Human Herpes Virus 8 (HHV-8)-Associated Multicentric Castleman Disease in an HIV Patient With Severe Immunosuppression: A Diagnostic Challenge.

Human herpes virus 8 (HHV-8)-associated multicentric Castleman disease (HHV-8-MCD) is a rare lymphoproliferative disorder that predominantly affects individuals with advanced immunosuppression, especially people living with HIV. The clinical picture frequently overlaps with opportunistic infections, lymphoma, and haemophagocytic lymphohistiocytosis, creating significant diagnostic challenges.  We present a case of a 51-year-old man recently diagnosed with HIV, who developed recurrent pyrexia, profound hyperferritinaemia, cytopenias, rapidly progressive lymphadenopathy, and escalating HHV-8 viraemia. Lymph node biopsy confirmed the diagnosis of HHV-8-positive MCD. Prompt initiation of rituximab and etoposide resulted in complete clinical and radiological remission.  The case highlights the importance of rapid recognition, timely histological confirmation, early initiation of rituximab-based therapy, and multidisciplinary management in HHV-8-MCD.