Oral Kaposi Sarcoma With Clinical Features Suggestive of Concurrent Multicentric Castleman Disease in Advanced AIDS

Kaposi sarcoma (KS) is an AIDS-defining malignancy associated with advanced HIV infection and human herpesvirus-8 (HHV-8). We report a case of biopsy-proven oral KS in a 31-year-old patient with advanced AIDS and clinical features suggestive of concurrent multicentric Castleman disease (MCD), highlighting the diagnostic complexity of overlapping AIDS-related conditions. We describe the clinical presentation, diagnostic evaluation, imaging findings, histopathologic features, and management of a 31-year-old man with advanced AIDS and antiretroviral nonadherence presenting with constitutional, gastrointestinal, and neurologic symptoms. Laboratory evaluation demonstrated profound immunosuppression, elevated HIV viral load, cytopenias, hepatocellular injury, and markedly elevated inflammatory markers. Physical examination revealed violaceous oral and cutaneous lesions. Infectious evaluation was largely unrevealing, while imaging demonstrated diffuse lymphadenopathy and inflammatory colitis. Histopathologic examination of an oral lesion confirmed KS with HHV-8 positivity. The combination of diffuse lymphadenopathy, systemic inflammation, and cytopenias raised concern for concurrent MCD. The patient was restarted on antiretroviral therapy (ART) and initiated on trimethoprim-sulfamethoxazole for Pneumocystis jirovecii pneumonia prophylaxis, with outpatient oncologic follow-up arranged. This case highlights the diagnostic complexity of advanced HIV infection, in which infectious, inflammatory, and malignant processes may coexist. Tissue diagnosis remains essential for distinguishing overlapping HHV-8-associated diseases and guiding management.