S2014 Disseminated Histoplasmosis Presenting as Right Colon Lesions in HIV-Negative Patients: Report of Two Cases

Abstract

Introduction: Histoplasma capsulatum is the most common endemic mycosis in the gastrointestinal tract of immunocompromised hosts. However, it can also present in immunocompetent patients. Terminal ileum and cecum are most commonly affected, recognized on endoscopic examination as inflammation, ulcerated lesions, or polypoid masses. In most patients, gastrointestinal manifestation takes a subclinical disease course. We present 2 cases of immunocompetent patients with colon lesions attributed to disseminated histoplasmosis. Case Description/Methods: First case is a 62-year-old African American woman admitted to the hospital due to abdominal pain, weight loss and poor oral intake. She was found to be anemic. CT revealed a large retroperitoneal mass with central necrosis suspicious for malignancy. Colonoscopy revealed a cecal ulcer (Figure A) with pathology reporting mucosal ulceration associated with granulomatous inflammation. GMS and PAS fungal stain showed small ovoid yeast forms, morphologically compatible with histoplasmosis (Figure B).Biopsy of the retroperitoneal mass was also positive for histoplasma. Second case is a 54-year-old Hispanic man admitted to the hospital with fluid overload secondary to acute renal failure attributed to post-infectious glomerulonephritis. He was also found to have anemia. Colonoscopy showed a 6 mm polyp in the ascending colon removed by cold snare technique (Figure C). Pathology reported polyp fragment with macrophages and numerous 2-4 micron non-budding yeast forms best seen on GMS stain, most consistent with histoplasmosis. CT scan showed prominent retroperitoneal lymphadenopathy. Both our patients were started in itraconazole and are being closely followed by the ID service. Discussion: Disseminated histoplasmosis is usually seen in immunocompromised patients such as those with HIV and medication-induced immunosuppression. GI involvement and symptoms can be diverse. Our first patient presented with a large retroperitoneal mass and cecal ulcer causing her abdominal discomfort. Second patient was much more subtle as histoplasmosis presented as a polypoid lesion. Both patients presented with significant anemia, which prompted endoscopic evaluation. Although the diagnosis of histoplasmosis in immunocompetent patients usually requires a high index of suspicion, gastroenterologists should be familiar with its variable presentations in the GI tract.Figure 1.: a) Histoplasma presenting as cecal ulcer. b) GMS stain showing Histoplasma. c) Polypoid lesion positive for Histoplasma.