Miller CQ, Saeed OAM, Collins K. Gastrointestinal histoplasmosis complicating pediatric Crohn disease: A case report and review of literature. World J Gastrointest Endosc 2022; 14(10): 648-656 [PMID: 36303809 DOI: 10.4253/wjge.v14.i10.648]
Corresponding Author of This Article
Katrina Collins, MD, Assistant Professor, Department of Pathology, Indiana University School of Medicine, 350 W 11th Street, Indianapolis, IN 46202, United States. katcoll@iu.edu
Research Domain of This Article
Infectious Diseases
Article-Type of This Article
Case Report
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
World J Gastrointest Endosc. Oct 16, 2022; 14(10): 648-656 Published online Oct 16, 2022. doi: 10.4253/wjge.v14.i10.648
Gastrointestinal histoplasmosis complicating pediatric Crohn disease: A case report and review of literature
C Quinn Miller, Omer A M Saeed, Katrina Collins
C Quinn Miller, Omer A M Saeed, Katrina Collins, Department of Pathology, Indiana University School of Medicine, Indianapolis, IN 46202, United States
Author contributions: Miller CQ served as the primary author; Miller CQ and Collins K are responsible for this literature review; Miller CQ, Saeed OAM, and Collins K were responsible in the construction of the manuscript; Collins K served as the senior author, provided invaluable educational input and managed the edits of the manuscript, and guided the primary author through the submission process; All authors read, revised, and gave approval of the manuscript.
Informed consent statement: All study participants or their legal guardian provided informed written consent about personal and medical data collection prior to study enrollment.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Katrina Collins, MD, Assistant Professor, Department of Pathology, Indiana University School of Medicine, 350 W 11th Street, Indianapolis, IN 46202, United States. katcoll@iu.edu
Received: July 17, 2022 Peer-review started: July 17, 2022 First decision: September 5, 2022 Revised: September 5, 2022 Accepted: September 21, 2022 Article in press: September 21, 2022 Published online: October 16, 2022
Abstract
BACKGROUND
Infection with Histoplasma capsulatum (H. capsulatum) can lead to disseminated disease involving the gastrointestinal tract presenting as diffuse abdominal pain and diarrhea which may mimic inflammatory bowel disease (IBD).
CASE SUMMARY
We report a case of 12-year-old boy with presumptive diagnosis of Crohn disease (CD) that presented with several months of abdominal pain, weight loss and bloody diarrhea. Colonoscopy showed patchy moderate inflammation characterized by erythema and numerous pseudopolyps involving the terminal ileum, cecum, and ascending colon. Histologic sections from the colon biopsy revealed diffuse cellular infiltrate within the lamina propria with scattered histiocytic aggregates, and occasional non-necrotizing granulomas. Grocott-Gomori’s Methenamine Silver staining confirmed the presence of numerous yeast forms suggestive of Histoplasma spp., further confirmed with positive urine Histoplasma antigen (6.58 ng/mL, range 0.2-20 ng/mL) and serum immunoglobulin G antibodies to Histoplasma (35.9 EU, range 10.0-80.0 EU). Intravenous amphotericin was administered then transitioned to oral itraconazole. Follow-up computed tomography imaging showed a left lower lung nodule and mesenteric lymphadenopathy consistent with disseminated histoplasmosis infection.
CONCLUSION
Gastrointestinal involvement with H. capsulatum with no accompanying respiratory symptoms is exceedingly rare and recognition is often delayed due to the overlapping clinical manifestations of IBD. This case illustrates the importance of excluding infectious etiologies in patients with “biopsy-proven” CD prior to initiating immunosuppressive therapies. Communication between clinicians and pathologists is crucial as blood cultures and antigen testing are key studies that should be performed in all suspected cases of histoplasmosis to avoid misdiagnosis and inappropriate treatment.
Core Tip: Impaired cell-mediated immunity is known to increase the risk for disseminated histoplasmosis and has been described in the setting of Crohn disease (CD) treated with immunosuppressant agents. Endoscopically, the appearance of histoplasmosis varies and includes features of inflammatory mucosal changes. Increasing awareness of this condition is critical to avoid misdiagnosis and inappropriate treatment, particularly in the setting of underlying CD. While no specific recommendations are available, immunosuppressive therapy may be safely initiated in some cases when there appears to be effective response to antifungal therapy and the patient can be monitored closely.
