S5145 When Histoplasma Hides: Dissemination Histoplasmosis With Gastric Involvement in an Immunocompetent Patient After 8 Years of Latency

Introduction: Histoplasmosis is a fungal infection endemic to the Ohio and Mississippi River valleys, primarily affecting the lungs via inhaled spores. It’s often mild or asymptomatic in immunocompetent individuals but can be life-threatening. When disseminated, it frequently involves the GI tract, especially the ileum and colon, due to lymphoid tissue abundance. Gastric involvement is rare but can mimic ulcers or cancer, delaying diagnosis. We report a case of recurrent disseminated histoplasmosis with gastric involvement in a patient with odynophagia in a non-endemic area. Case Description/Methods: A 71-year-old man with prior tonsillar histoplasmosis treated 8 years ago with 12 weeks of itraconazole and confirmed resolution presented with 2 weeks of progressive odynophagia (worse with solids), oral ulcers, abdominal pain, and 30-pound weight loss over 6 months. He denied dysphagia, nausea, vomiting, and melena. No history of malignancy, autoimmune diseases, steroids use or recent travel. Vitals were stable. Labs showed normocytic anemia (Hb 6.7 g/dL, MCV 92.7) without leukocytosis or thrombocytopenia. Kidney and liver functions were normal. Infectious workup, including HIV and tick-borne diseases, was negative. Computerized tomography of the chest showed tree-in-bud centrilobular nodules with upper lobe predominance. Abdominal imaging was unremarkable. Esophagogastroduodenoscopy (EGD) done to evaluate his odynophagia, revealing multiple gastric ulcers with overlying eschar, the largest being 40 mm in diameter. Biopsies showed chronic gastritis with ulceration and fungal yeasts consistent with Histoplasma, confirmed by Grocott's methenamine silver stain. Similarly, oral ulcer biopsy showed non-necrotizing granulomas with fungal forms. He was started on itraconazole and was discharged in stable condition. Follow-up EGD 1 month later showed healing ulcers. Discussion: Disseminated histoplasmosis involving the GI tract is common, typically seen in immunocompromised patients. Recurrence may occur due to fungus' ability to persist within macrophages but is extremely rare in immunocompetent individuals. To our knowledge, this is the first reported case of recurrent gastric involvement in an immunocompetent patient from a non-endemic area. This case underscores the need for high clinical suspicion and prompt histopathological evaluation when ulcers are found on endoscopy, even in immunocompetent individuals, to ensure timely diagnosis and optimal outcomes.