A Rare Case of Gastrointestinal Histoplasmosis in an Immunocompromised Host

Abstract

Introduction: Histoplasmosis capsulatum (HC) is a dimorphic fungus common to the Ohio and Mississippi River valleys and is found mainly in soil enriched by avian or bat droppings. It typically presents as an asymptomatic pulmonary infection. Gastrointestinal (GI) involvement is usually unrecognized due to nonspecific symptoms and is thought to be symptomatic in only 3 to 12% of patients. The majority of GI histoplasmosis involves patients with HIV/AIDS. The most common site of GI involvement is the ileocecal region due to the presence of abundant lymphoid tissue. Case Presentation: A 64-year-old man with paroxysmal atrial fibrillation (on warfarin), end stage renal disease on hemodialysis, status post failed transplanted kidney and on chronic immunosuppression presented with a one day history of hematochezia and hematemesis and six weeks of worsening left lower quadrant abdominal pain. CT thorax with intravenous contrast revealed a right lower lobe cavitary mass and a spiculated left upper lobe nodule (Figure 1). Esophagogastroduodenoscopy with enteroscopy revealed old blood in stomach and the endoscope was advanced into the jejunum revealing multiple ulcers (Figure 2). Histopathology from jejunal biopsies was consistent with HC (Figure 3). Histoplasmosis antibodies by complement fixation for yeast and mycelia were positive as was fungal immunodiffusion for Histoplasma M antigen. Histoplasmosis serum antigen was negative. The patient was treated with intravenous amphotericin for presumed disseminated histoplasmosis. He improved clinically with resolution of symptoms and was discharged on oral itraconazole and remains therapeutic five months later.Figure: CT thorax with intravenous contrast showing (A) 21mm right lower lobe cavitary mass (B) and 19mm left upper lobe spiculated nodule.Figure: Ulcerations of proximal (A) and mid-jejunum (B).Figure: Gomori methenamine silver (GMS) stain of jejunal biopsy specimen showing budding yeast form of histoplasmosis capsulatum.Discussion: Histoplasmosis capsulatum is generally seen in immunocompromised hosts. While common at autopsy, gastrointestinal histoplasmosis (GIH) goes unrecognized during life as the symptoms are nonspecific. Patients with GIH most commonly present with abdominal pain and diarrhea, but may also have dysphagia, odynophagia, bowel obstruction or perforation. In this case, the patient presented with clinically significant gastrointestinal bleeding. Upper endoscopy with jejunal biopsies revealed HC. Both the presence of symptomatic GIH and the jejunal location are atypical. This observation in a patient without HIV is exceedingly rare.