Fatal chronic disseminated histoplasmosis with massive gastrointestinal bleeding in an immunocompetent elderly Singaporean male without recent travel

Background: Although endemic in surrounding countries, the true burden of histoplasmosis in Singapore is not well-defined and likely underestimated due to under-diagnosis. This case report describes a case of fatal chronic disseminated histoplasmosis in an elderly immunocompetent Singaporean male without recent travel. Case Report: A 77-year-old male presented with a 3-month history of generalised weakness and loss of weight. As investigations revealed bilateral calcified pulmonary nodules, bilateral adrenal enlargement, cytopenias, and non-parathyroid hormone-mediated hypercalcaemia, he was evaluated for tuberculosis. He later developed massive gastrointestinal bleeding and he underwent emergent endoscopy that revealed ulcerative nodular lesions in the duodenum and throughout the colon. Biopsies of the lesions showed numerous 2–4 μm intracellular yeasts within histiocytes in the lamina propria, suggestive of histoplasmosis. Based on the pathological finding, he was started on amphotericin B on day 26 of admission, but passed away 1 day later from refractory hypotension. Histoplasma capsulatum eventually grew on fungal blood culture. Conclusion: This case highlights the need for greater awareness of histoplasmosis among clinicians in Singapore. Because Histoplasma capsulatum can reactivate several years after exposure, and chronic disseminated histoplasmosis can occur in the immunocompetent elderly, histoplasmosis should be considered and specific diagnostic testing be undertaken whenever there is a compatible clinical syndrome, regardless of travel history and immune status. As disseminated histoplasmosis can be fatal, a high index of clinical suspicion is crucial to ensure timely diagnosis and treatment.