Abstract Background Crohn’s disease may present with ileal ulcerations and extraintestinal manifestations such as seronegative spondyloarthritis. In rare cases, infectious comorbidities like intestinal histoplasmosis may coexist, complicating diagnosis and therapeutic decisions. We report an exceptionally rare case of CD with persistent ileal ulcerations later attributed to coexisting intestinal histoplasmosis in an immunocompetent patient without pulmonary involvement. Methods A 22-year-old male with HLA-B27 positive seronegative spondyloarthritis was evaluated for chronic diarrhoea and lumbar pain. Initial colonoscopy revealed ulcerations in the ileocaecal valve and distal ileum; upper endoscopy was unremarkable. Based on clinical, endoscopic, and biochemical findings—including elevated faecal calprotectin (785 µg/g) a diagnosis of Crohn’s disease was established, and ustekinumab was initiated due to axial involvement. Capsule endoscopy corroborated multiple ulcerations in the distal ileum. The patient showed significant clinical improvement, with normalisation of stool frequency, resolution of lumbar pain, stable weight, and a decrease in calprotectin to 85 µg/g. A colonoscopy was later performed to assess mucosal response, revealing persistent ileal ulcerations. Given the unexpected findings, new biopsies were obtained and stained with PAS, identifying fungal elements consistent with intestinal histoplasmosis. These findings confirmed the coexistence of both Crohn’s disease and intestinal histoplasmosis.Tuberculosis was excluded by negative intestinal cultures and Quantiferon testing. Immunoglobulin levels were normal, and pulmonary involvement was excluded through clinical and radiological evaluation. Results A multidisciplinary team including gastroenterology, immunology, and infectology—decided to maintain ustekinumab and initiate itraconazole. No systemic symptoms or immunosuppressive complications were observed during follow-up. Conclusion This case highlights the diagnostic and therapeutic complexity of Crohn’s disease with superimposed intestinal histoplasmosis. The coexistence of both entities without pulmonary involvement and in an immunocompetent host—is extraordinarily rare. Diagnosis was supported by clinical, endoscopic, biochemical, and histological findings. Early recognition and coordinated management were essential to avoid therapeutic delays and complications. Clinicians should maintain a high index of suspicion for dual pathology in IBD patients with atypical or persistent endoscopic lesions, even in the absence of systemic symptoms. References: 1. Shojaei E, Walsh JC, Sangle N, et al. Gastrointestinal histoplasmosis mimicking Crohn’s disease. Open Forum Infect Dis. 2021;8(7):ofab249. doi:10.1093/ofid/ofab249 2. Jiménez-Rivera E, Dávila-Ruiz EO, García-Manzano RA, et al. Intestinal histoplasmosis in immunocompetent patient: an unusual cause of massive small intestine bleeding.Rev Med Hosp Gen Méx. 2021;84(3):123–130. doi:10.24875/hgmx.20000062 3. Guillo L, D’Amico F, Danese S, Peyrin-Biroulet L. Ustekinumab for extra-intestinal manifestations of inflammatory bowel disease: a systematic literature review. J Crohns Colitis. 2021;15(7):1236–1243. doi:10.1093/ecco-jcc/jjaa260. Conflict of interest: Dr. Pacheco Oliva, Jorge: The author declares no conflicts of interest. Melendez, Ninoska: The author declares no conflicts of interest. Sanchez, Abel: The author declares no conflicts of interest.
Oliva et al. (Thu,) studied this question.