HHV-8-ASSOCIATED MULTICENTRIC CASTLEMAN DISEASE IN AN HIV CARRIER COMPLICATED BY HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS AND TUMOR LYSIS SYNDROME: ATYPICAL PRESENTATIONS IN A RARE LYMPHOPROLIFERATIVE DISORDER

Introduction/Objective: Human herpesvirus-8 (HHV-8)-associated multicentric Castleman disease (MCD) is a rare lymphoproliferative disorder sometimes associated with acquired human immunodeficiency syndrome. Hemophagocytic lymphohistiocytosis (HLH) and tumor lysis syndrome (TLS) are unusual complications of MCD. Here, we presented a case report of an HIV patient with MCD who evolved for HLH and TLS, atypical presentations in this clinical setting. Methods: Data were obtained reviewing the medical record of a patient diagnosed and treated at the University of São Paulo (USP) in 2023. Case report: A 31 year-old man was admitted at the emergency department of HC-USP in June 2023 presenting multiple adenomegalies, recurrent fever and weight loss during the past 4 months. He had a previous diagnosis of HIV infection in regular treatment, with a T-CD4 lymphocyte count = 514 copies/mL. The patient was previously admitted in another service due to infectious complications, where he underwent an axillary lymph node biopsy, which showed lymphoid hyperplasia rich in interfollicular plasmocytes, compatible with a HHV-8-associated MCD, in addition to a spindle-cell neoplastic proliferation, supporting theconcomitant diagnosis of Kaposi's sarcoma (KS). He was submitted to up-front treatment based on prednisone 1 mg/kg/day. Upon admission at the HC-USP, he presented hepatosplenomegaly, ascites, and multiple lymph node enlargement. Laboratory evaluation revealed anemia, thrombocytopenia, hypoalbuminemia and marked increase in inflammatory tests, fulfilling criteria for MCD activity. After 10 days, he evolved with worsening of hepatosplenomegaly, progressive increase of direct bilirubin, pancytopenia, hyperferritinemia and hypertriglyceridemia. He also had TLS requiring dyalisis. Due to this presentation, a bone marrow evaluation was performed, which showed many figures of hemophagocytosis and high EBV viral load measured by qRT-PCR. The H-Score was applied to this case, with a result of 228 points, inferring 98-99% probability of HLH diagnosis, compatible with the previously formulated hypothesis. Promptly, methylprednisolone pulsotherapy was started at a dose of 1 g/day I.V. and etoposide 50 mg/m2/day I.V. for 3 days. Despite this approach, the patient presented an unfavorable evolution, evolving to death before the institution of up-front treatment for HHV-8-MCD. Discussion: HLH is a potentially lethal condition caused by macrophage hyperactivation following inflammatory