Pigmented mesenteric lymphadenopathy in familial adenomatous polyposis - an unusual cause of intraoperative abandonment of ileo-anal pouch

Familial adenomatous polyposis (FAP) is an autosomal dominant condition with near complete penetrance, characterised by the presence of numerous adenomatous polyps of the colon and rectum. Melanosis coli describes the brownish-black discolouration of the colon resulting from the accumulation of a granular pigment in the phagosomes of macrophages in the colonic lamina propria. The presence of melanosis pigment in pericolonic lymph nodes has been reported in patients with coincidental melanosis coli, following segmental colonic resection. We report a unique case of FAP with melanosis pigment in lymph nodes in the small bowel mesentery that initially prevented a restorative proctocolectomy but that resolved following a colectomy, subsequently facilitating formation of an ileo-anal pouch.