S2172 A Unique Case of Disseminated Histoplasmosis Presenting as Colonic Ulcers

Abstract

Introduction: Histoplasmosis is the most common endemic mycosis in the United States with a disseminated form usually only seen in immunocompromised patients. While localized infections are usually self-limiting and often asymptomatic, some patients present with extra-pulmonary disseminated disease. Although case reports have described colonic and ileal involvement, gastrointestinal manifestations are uncommon. Here we report isolated colonic involvement of disseminated histoplasmosis in an asymptomatic patient. Case Description/Methods: A 62-year-old male with a history of end stage renal disease secondary to IgA nephropathy status post living donor renal transplant on chronic immunosuppressive therapy presented for a routine screening colonoscopy. The patient denied gastrointestinal and pulmonary symptoms to include: cough, shortness of breath, fever, abdominal pain, diarrhea and gastrointestinal bleeding. He grew up in the state of Mississippi and currently resides in Texas working in landscaping. Within the cecum, there were 2 discrete areas of abnormal appearing tissue (Figure A). A 10mm irregular, superficial ulcer with no high-risk stigmata for bleeding was also noted within the distal transverse colon (Figure B). Cold forceps biopsies were obtained at both sites. Surgical pathology with Grocott’s methenamine silver stain demonstrated abundant intra-histiocytic and extracellular organisms morphologically compatible with histoplasmosis. Given a potential for fungal morphological mimicry, the patient was serologically tested for histoplasmosis, coccidioides, and blastomyces. Ultimately, PCR from the tissue sample taken during the biopsy tested positive for Histoplasma capsulatum. The patient was started on itraconazole for 12 months duration which he tolerated without side effects and remained asymptomatic on follow up. Discussion: This case demonstrates an unusual presentation of disseminated histoplasmosis with asymptomatic colonic involvement including the variable endoscopic appearance of this fungal infection. With a mortality rate as high as 31% in the immunocompromised population gastroenterologists need to remain cognizant when encountering colonic ulcerations or abnormal mucosa in high risk patients. In addition, this case highlights the importance of tissue sampling to secure the diagnosis along with the efficacy of itraconazole in treating this potentially deadly infection.Figure 1.: A. Discrete area of anomalous tissue in the cecum B. Area of ulceration along the distal transverse colon.