Histoplasma capsulatum is a dysmorphic fungus distributed worldwide commonly associated with pulmonary histoplasmosis. We report the case of an unusual presentation of gastrointestinal histoplasmosis leading to the obstruction of the intestinal lumen in a 30-year-old female, HIV positive, admitted to the hospital due to chronic abdominal pain and constipation. An initial abdominal CT revealed a mass in the sigmoid colon. A further colonoscopy showed an infiltrating, friable mass obstructing 80% of the lumen staining positive for H. capsulatum. The unspecific nature of the patient's symptoms along with the unusual presentation of the infection raises awareness about the importance of including new pathologies to differential diagnoses when treating AIDS patients.