337 Leishmaniasis in Fever of Unknown Origin: Importance of Bone Marrow Evaluation

Introduction/Objective Persistent fever in immunocompromised patients can be a diagnostic challenge, especially when common infectious causes are ruled out. Visceral leishmaniasis, though rare outside endemic regions, should remain a consideration in such cases due to its potentially fatal nature if missed. Methods/Case Report We present a 20-year-old male with a history of sarcoidosis on chronic immunosuppressive therapy, who presented with persistent fever, weight loss, gum hypertrophy, and generalized lymphadenopathy. Examination revealed pallor and hepatosplenomegaly. Family history was notable for liver cirrhosis and tuberculosis. Initial workup included differential diagnoses such as pyrexia of unknown origin, malignancy, toxoplasmosis, and tuberculosis. A right axillary lymph node biopsy showed granulomatous inflammation, morphologically favoring toxoplasmosis. However, bone marrow examination revealed hypercellular marrow (60–80%), trilineage hematopoiesis, dyserythropoietic changes, and infiltration by organisms morphologically consistent with Leishmania. The presence of kinetoplasts on Giemsa/Wright stain confirmed the diagnosis, clearly distinguishing it from other mimics. Numerous macrophages packed with amastigotes indicated a high parasitic burden, and PCR testing corroborated the findings. Results NA Conclusion This case highlights the diagnostic utility of bone marrow examination in evaluating prolonged fever when initial findings are inconclusive and highlights the need to maintain a broad differential, even in non-endemic regions, for timely and life-saving diagnosis.