Question: A 16-year-old girl with a 2-year history of ulcerative colitis was referred to our university hospital because of fever, vomiting, and epigastric pain for 10 days; bloody diarrhea during the last month; and a rapid involuntary weight loss (5 kg). Sixth months earlier, during remission with oral mesalamine (60 mg/kg), she suffered a mild-to-moderate ulcerative colitis flare-up requiring oral prednisolone (1 mg/kg for 2 weeks and then tapered). At admission, physical examination showed pallor, mild signs of dehydration, and diffuse abdominal pain without signs of peritoneal irritation. Written consent for publication was obtained from the patient and her parents. Laboratory investigations revealed anemia, mild eosinophilia, hypoalbuminemia, an increased erythrocyte sedimentation rate, and fecal calprotectin. Specific serologic tests and blood and stool cultures for bacteria and viruses were negative. Colonoscopy showed pancolitis with continuous diffuse granular and friable mucosa (Mayo Score of 2) and upper endoscopy showed antral gastritis and diffuse duodenitis with nonbleeding erosions. The patient was started on steroids (1 mg/kg) followed by the amelioration of diarrhea, but persistence of mild grade fever and vomiting. Histologic examination showed crypt distortions and abscesses associated with goblet cell depletion. An upper endoscopy showed a normal esophageal and gastric mucosa. Duodenal histology (periodic acid–Schiff staining method) is presented in Figure A. What is the diagnosis? See the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. Aspergillus fumigatus was identified in duodenal biopsy specimens. Serum galactomannan antigen test (Bio-rad Platelia Aspergillus Ag kit) and specific IgM (DRG IgM ELISA) assays were positive (index 4.1 and 6.5 UI/mL, respectively); chest and brain computed tomography scans were normal.1Donnelly J.P. Chen S.C. Kauffman C.A. et al.Revision and update of the consensus definitions of invasive fungal disease from the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium.Clin Infect Dis. 2020; 71: 1367-1376Crossref PubMed Scopus (898) Google Scholar Antifungal treatment with voriconazole (loading dose: 6 mg/kg/12 h on the first day, then 4 mg/kg/12 h) was started and steroids were tapered.2Patterson T.F. Thompson 3rd, G.R. Denning D.W. et al.Practice guidelines for the diagnosis and management of aspergillosis: 2016 update by the Infectious Diseases Society of America.Clin Infect Dis. 2016; 63: e1-e60Crossref PubMed Scopus (1405) Google Scholar A comprehensive immune assessment was performed after discontinuing steroid therapy. After 1 week of treatment, the clinical condition and inflammatory markers improved. Aspergillus fumigatus is a ubiquitous saprophytic fungus with low pathogenicity in healthy individuals, but may be the major cause of life-threatening infection in immunocompromised individuals. Enteric aspergillosis is an uncommon presentation of invasive aspergillosis, which can disseminate hematogenously to other organs. Clinical features of invasive aspergillosis include abdominal pain, fever, and hematochezia or peritonitis subsequent to bowel ischemia or perforation; typical endoscopic findings include ulcerations or islands of necrotic tissue. Glucocorticosteroids are critical in the management of inflammatory bowel disease (IBD), but are associated with increased risk of opportunistic infections due to immune suppression. It should also be emphasized that IBD itself predisposes to infective complications3Kucharzik T. Ellul P. Greuter T. et al.ECCO guidelines on the prevention, diagnosis, and management of infections in inflammatory bowel disease.J Crohns Colitis. 2021; 15: 879-913Crossref PubMed Scopus (70) Google Scholar and that gastrointestinal infections can be potential triggers for IBD relapse.