Challenging Aspects of Familial Adenomatous Polyposis With Malignant Transformation: A Report of Two Cases

Familial adenomatous polyposis (FAP) is a genetic disorder characterized by the early onset of hundreds of polyps in the gastrointestinal tract, mainly in the colon and rectum. Despite its rarity, data on FAP in Morocco remain limited due to the absence of a national registry and comparative case series. We present two cases of FAP diagnosed in Morocco. The two patients, one male and one female, had a mean age of 34 years. Initial colonoscopy revealed more than 100 polyps for both patients. The polyps varied in size and morphology, including flat, sessile, and pedunculated forms, and were distributed throughout the colon and rectum, and all showed adenomatous features on virtual chromoendoscopy. Histopathological examination of the polyps revealed a range of findings, from low-grade tubulovillous adenomas to moderately differentiated rectal adenocarcinoma. Esophagogastroduodenoscopy (EGD) revealed duodenal polyps, with histology confirming tubular adenomas exhibiting both low- and high-grade dysplasia. Both patients underwent surgery: one had a subtotal colectomy with ileorectal anastomosis, and the other a total proctocolectomy with ileoanal anastomosis. The clinical evolution was marked by the development of colon adenocarcinoma in one patient and rectal adenocarcinoma in the other. Regular surveillance of the duodenal polyps was recommended every 1-2 years.