Enteritis cystica profunda is a rare and benign disease defined as the invagination of the intestinal epithelium into the submucosa and more profound layers of intestinal wall leading to the formation of mucin-filled cystic spaces. We reported the case of a 45-year-old female, suffering from a Crohn’s disease, with a Koenig’s syndrome, diarrhea, abdominal pain and weight loss. The colonoscopy and the abdominopelvic scan showed a terminal ileal stenosis, with parietal calcifications. A surgical ileocecal resection was decided. Gross examination of the ileocecal resection showed a thickening of the ileal wall, with many mucin-filled cysts measuring 1mm to 2cm, with some calcifications. The ileal mucosa was ulcerated, and showed a stenotic sector extending over 3cm. Histological examination showed acute ulcerated ileitis lesions, with chronic ileitis lesions and stenosis, compatible with the known diagnosis of Crohn’s disease. There were also many cysts into the ileal wall. They were lined with a regular ileal epithelium. The cysts contained mucus, with some calcifications. Some cysts were ruptured, with extravasation of mucus within the wall. Cystica profunda can be found anywhere along the digestive tract. The physiopathology is not yet well understood, but it seems to be favored by chronic aggression of the intestinal wall. This pathology most often coexists with Crohn’s disease. The main differential diagnosis is mucinous adenocarcinoma. Cystica profunda does not require any specific treatment.Copyright © 2023 Elsevier Masson SAS. All rights reserved.