Congenital Hypertrophy Retinal Pigment Epithelium as a Manifestation of Colon Cancer

Abstract

Purpose: Congenital hypertrophy of retinal pigment epithelium (CHRPE) is a benign lesion of the optic fundus that is an associated extracolonic manifestation of familial adenomatous polyposis (FAP). However, there are no reports of its association with a solitary colonic neoplasm. To our knowledge, we present the first case of CHRPE in a patient with a solitary colonic neoplasm. A 73-year old female with past medical history of cataracts was following a retina specialist for a routine examination. Upon examination she was found to have acute, multiple CHRPE lesions in both eyes (Figure A). Her previous fundoscopic exam did not show any CHRPE lesions. She was referred to a gastroenterologist for immediate colonoscopy. The patient never had a screening colonoscopy in the past. She had a history of long-term constipation, but no hematochezia, change in bowel habits, or change in bowel caliber. There was no family history of colon cancer or familial adenomatous polyposis (FAP). The colonoscopy showed a fungating non-obstructing mass, 25 mm from the anal verge, encompassing one-third of the circumference of the sigmoid lumen (Figure B). Biopsies were taken, which showed high-grade dysplasia. The patient had an exploratory laparotomy and colon resection with primary end-to-side anastomosis. The pathology confirmed tubular villous adenoma. The margins were free of malignancy with 17 benign lymph nodes. CT scan showed no metastasis. The patient tolerated the procedure well and was discharged 6-days post-op without any need for chemotherapy or radiation. CHRPE is a flat, black, well-defined lesion of the retinal pigment epithelium. This fundoscopic finding is almost always benign, and estimates of its prevalence in the normal population vary widely (0.3%-40%). However, it is a phenotypical extracolonic manifestation of FAP when found acutely and in bilateral retinas. It is thought that since CHRPE is not an age-dependent lesion it could provide a useful marker of patients with a germline APC gene mutation; however, several authors have studied this with inconclusive results. The setting for this case, however, is different than most; to our knowledge, this is the first case of a CHRPE patient who did not have a medical or family history of FAP presenting with a solitary colonic neoplasm.Figure: A: Black arrows point to multiple CHRPE lesions seen on fundoscopic exam. Figure B: Mass seen in sigmoid.