Kaposi Sarcoma Presenting as Hemophagocytic Lymphohistiocytosis Mimicking Infection and Lymphoma: A Diagnostic Challenge.

Kaposi sarcoma (KS) is an angioproliferative malignancy associated with human herpesvirus 8 and typically presents with cutaneous lesions. Visceral involvement and presentation as secondary hemophagocytic lymphohistiocytosis (HLH) are rare and may obscure the underlying diagnosis. A 45-year-old woman with hepatitis B carrier status and compensated cirrhosis presented with dizziness, fever, rash, fatigue, cytopenias, and hepatosplenomegaly. Laboratory evaluation revealed normocytic anemia, thrombocytopenia, elevated transaminases, and markedly increased inflammatory markers, prompting hospitalization for suspected infection and hematologic disease. Despite broad antimicrobial therapy and extensive investigations, her condition progressed with persistent inflammation, raising the suspicion of secondary HLH. Empirical treatment with etoposide and dexamethasone was initiated. Positron emission tomography demonstrated hypermetabolic bilateral axillary lymphadenopathy, and excisional biopsy of the right axillary lymph node revealed KS. The patient was transferred to oncology care, where therapy was changed to etoposide plus paclitaxel with clinical stabilization. KS presenting as secondary HLH is extremely uncommon and poses significant diagnostic challenges, particularly in the absence of typical cutaneous findings. This case underscores the importance of considering occult malignancy in patients with fever, cytopenias, and hepatosplenomegaly who do not respond to conventional therapy. Timely tissue diagnosis is crucial in patients with suspected HLH when the underlying cause is unclear, as the early identification of malignancy can significantly alter management and improve outcomes.