An Extremely Rare Presentation of Mucinous Adenocarcinoma Originating From Meckel Diverticulum Masquerading in a Young Woman With Crohn's Disease.

Mucinous adenocarcinoma with signet cell features originating from Meckel diverticulum (MD) is an extremely rare primary malignant tumor. A woman in her 30s presented with multiple episodes of vomiting, abdominal pain, and constipation. She had a history of stricturing Crohn's disease and managed well with steroids, azathioprine, and infliximab. This time, a computed tomography scan showed distal ileal small-bowel obstruction. Urgent surgery for a nonsettling small bowel obstruction was performed. MD was incidentally found and was concerning for malignancy. This case report illustrates how this extremely rare malignancy was behaving like Crohn's disease, which delayed the diagnosis and treatment.