[Gastrointestinal histoplasmosis: an atypical presentation]

Area of Science:

• Infectious Diseases
• Gastroenterology
• Mycology

Background:

• Histoplasmosis, a systemic mycosis caused by Histoplasma capsulatum, is endemic in the Americas and can affect any organ.
• It is more prevalent in immunodeficient individuals and is the most common opportunistic mycosis associated with Human Immunodeficiency Virus (HIV).
• Exclusive gastrointestinal involvement is rare, often fatal without treatment, and typically undiagnosable by macroscopic lesion appearance alone.

Observation:

• A 43-year-old male presented with a year of intermittent proctorrhagia and proctalgia, with no other symptoms.
• Videocolonoscopy revealed lesions in the terminal ileum and rectum, distinct from normal colonic appearance.
• Proctologic examination identified internal congestive hemorrhoids, but biopsies of ileal and rectal lesions confirmed Histoplasma.

Findings:

• The patient was diagnosed with HIV/AIDS, underscoring the link between immunosuppression and opportunistic infections.
• Histoplasmosis was confirmed via endoscopic biopsies of lesions with differing morphologies in the terminal ileum and rectum.
• This case represents an atypical presentation of histoplasmosis due to its exclusive gastrointestinal localization in an asymptomatic individual with previously undiagnosed HIV/AIDS.

Implications:

• This incidental endoscopic diagnosis significantly altered the patient's prognosis and life expectancy.
• The distinct endoscopic lesions observed in the rectum may serve as a rare diagnostic clue for histoplasmosis.
• Raising awareness among endoscopists about these specific endoscopic findings can aid in the early diagnosis of gastrointestinal histoplasmosis.