The great bur rare mimicker

We present a case of a previously asymptomatic middle-aged man, known for diverticulosis, Binet A
chronic lymphatic leukemia and psoriatic arthritis, who is admitted at the gastro-enterology department for 5 weeks lasting
bloody diarrhea associated with a 33lbs (15kg) weight loss. At admission, his abdomen is diffusely tender by palpation
and slightly distended without signs of systemic toxicity. CT scan reveals a pancolitis with involvement of terminal
ileum and prominent vascular congestion. There are no signs of perforation. On initial flexible rectosigmoïdoscopy,
rectosigmoïditis with ulcerative proctitis and negative biopsies for ischemia, inflammatory bowel disorder, neoplasia,
CMV, TBC and spirochete is seen. Fecal cultures for c. difficile, classic enteropathogens, Giardia and Cryptosporidium
are negative. Broad spectrum antibiotics are started and by means of additional histologic evidence a new ileocolonoscopy
is undertaken few days later. There is no change in endoscopic appearance with diffuse colonic erythema and edema
hampering progression beyond the splenic flexure. In suspicion of acute severe ulcerative colitis (ASUC) high dose
intravenous corticosteroids are initiated. Three days later the patient deteriorates with absent bowel sounds, aggravating
pain symptoms and pneumoperitoneum on CT scan, suggestive for colonic perforation ultimately leading to subtotal
colectomy with protective ileostomy. Examination of the pathology specimen reveals circumferential ulceration with
scarring, a thickened venous wall with active inflammation and fibrotic changes that consequently produce obstruction
of the venous lumen in the subserosa. A diagnose of Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is
made, a very uncommon and poorly understood ischemic disease affecting mainly the rectosigmoid colon of relatively
young, otherwise healthy males. It is a great mimicker of IBD, only diagnosed on histopathology of resected perforated
colon specimens after failed therapy lines. There is no known treatment for IMHMV but fortunately IMHMV patients
whose affected colon has been resected appear to be cured, with no recurrence of disease-related activity or symptoms
as is the case for this patient