Concurrent HHV-8-Associated Multicentric Castleman Disease and Kaposi Sarcoma in an HIV-Negative Patient: A Case Report

Background: Human Herpesvirus 8-associated multicentric Castleman disease is a rare, lymphoproliferative disorder characterized by recurrent episodes of systemic inflammation. The disease is predominantly observed in human immunodeficiency virus-positive patients, but there is evidence of its occurrence in negative individuals. Its pathogenesis is driven by dysregulated cytokine activity, particularly interleukin 6. Additionally, these individuals have an increased risk of developing Kaposi Sarcoma, which may present simultaneously. Case Presentation: The current paper presents a case of a 58-year-old male patient admitted to the Hematology Department of the Emergency City Hospital in Timisoara, Romania, in October 2024, accusing fever, night sweats, palpitations, weight loss and general deterioration, approximately three months prior, with gradual progression. Clinical examination revealed bilateral lymphadenopathy in the cervical and inguinal regions. No cutaneous lesions were observed initially. Laboratory tests showed elevated inflammatory markers, pancytopenia, hypergammaglobulinemia and hyponatremia. HIV serology had negative results. CT imaging revealed extensive lymphadenopathy and splenomegaly. Further excisional biopsy of the inguinal and cervical lymphadenopathies was performed. Following the microscopic examination, the final diagnosis of Human Herpesvirus 8-associated multicentric Castleman disease concurrent with Kaposi Sarcoma was established. Conclusions: Human Herpesvirus 8-associated multicentric Castleman disease is predominantly observed in HIV-positive patients, but there is evidence of its occurrence in human immunodeficiency virus-negative individuals, presenting distinct epidemiological and pathological characteristics. Early and precise diagnosis is essential, as the disease can progress rapidly and may lead to severe or fatal outcomes.