Noninvasive Colonic Phaeohyphomycosis Caused by Exophiala Oligosperma in a Patient With Crohnʼs Disease

Abstract

Introduction:Exophiala oligosperma is an uncommon fungal pathogen which can cause infection in immunocompromised patients. The majority of these infections are cutaneous, but fatal systemic infections have been reported. There are no reported cases of E. oligosperma causing colonic infection in the literature. To the best of our knowledge, this is a first reported case of an E. oligosperma induced non-invasive colonic phaeohyphomycosis in an immunocompromised patient with Crohn's disease treated successfully with voricanozole. Case Report: A 27 year old female with Crohn's disease on adalimumab and prednisone presented with persistent fever for three weeks. Index Crohn's symptoms were improving since initiation of adalimumab but diarrhea continued. The patient had no abdominal tenderness. Labs were remarkable for only mild anemia. After extensive work up, only colitis was noted on an abdominal computed tomography (CT) scan. A colonoscopy was done to attempt to further assess source of fever which showed worsened sigmoid colitis with pseudopolyps. Random biopsies showed inflammation. Multiple tissue samples cultured grew black mold with speciation consistent with E. oligosperma. Tissue biopsies did not show invasive fungal elements. Adalimumab was discontinued and patient was started on voricanozole. Fever resolved and the patient reported improvement in diarrhea after starting antifungal therapy. Discussion:E. oligosperma is a fungal strain that was indentified in 2003 by de Hoog et al.There are only six reported cases of phaeohyphomycosis associated with E. oligosperma in the literature. Cutaneous infections are more common with this pathogen but invasive infections are reported, including prosthetic valve endocarditis, dialysis-associated peritonitis, and disseminated infections. We describe a case of noninvasive colonic phaeohyphomycosis associated with E. oligosperma manifested by fever and gastrointestinal symptoms. Gross appearance of colon mucosa can look inflamed or darkly pigmented. Tissue culture is often needed for diagnosis. Histological finding of granulation suggests invasive infection. Superficial colonic mucosal infection can be treated with voricanozole; however, invasive phaeohyphomycosis usually requires surgical resection.