Histoplasmosis is a fungal infection caused by the dimorphic fungus Histoplasma capsulatum, acquired through inhalation. In immunocompetent individuals, primary infection is usually self-limited or asymptomatic. However, in immunocompromised patients, the pathogen can cause severe disseminated histoplasmosis with multisystem involvement, high fungal load, and high mortality risk in the absence of early diagnosis and treatment. This report describes a case of intestinal histoplasmosis in a severely immunosuppressed patient as the first manifestation of AIDS.

Female, 36 years old, with a 5-month history of progressive dysphagia and wasting syndrome, with no previous comorbidities. She sought medical care for abdominal pain and evolved with perforated acute abdomen. Abdominal CT showed segmental thickening of intestinal loops, lymphadenopathy, pneumoperitoneum, and free peritoneal fluid. Exploratory laparotomy revealed fecal peritonitis and jejunoileal perforation. The resected intestinal segment measured 12.5 cm in length and 2.5 cm in average diameter, with a dark-brown serosa covered by yellow-green material and an annular constriction area measuring 1.0 cm in diameter with a 0.3 × 0.3 cm ulcer located 6.5 cm from the nearest margin. The remaining mucosa preserved normal folds. Histology revealed dense mononuclear infiltrate and macrophages filled with structures morphologically compatible with Histoplasma capsulatum, positive for PAS and Grocott stains. The patient was diagnosed with HIV infection during hospitalization, presenting severe immunodeficiency (CD4⁺ T-cell count: 28 cells/mm³), and progressed to death due to septic shock.

A CD4⁺ T-cell count below 200 cells/mm³ defines AIDS, indicating advanced immunodeficiency and significant predisposition to opportunistic infections such as disseminated histoplasmosis. In this case, the patient had no prior HIV diagnosis, and intestinal histoplasmosis represented the initial manifestation of AIDS. The clinical presentation and progression emphasize the importance of early HIV diagnosis, particularly in young adults with wasting syndrome and progressive dysphagia. A high index of suspicion for opportunistic infections must be maintained, even in atypical presentations, given the wide spectrum of manifestations these conditions may assume in immunosuppressed individuals.