Squamous cell carcinoma complicating idiopathic inflammatory bowel disease.

Squamous cell carcinoma of the colon and rectum, originating proximal to the transitional zone, is a rare complication of idiopathic inflammatory bowel disease (IIBD). To date there are only 15 single case reports of such an occurrence. This carcinoma develops more commonly in females and in patients with pancolonic disease of more than 8 years' duration. The rectum is affected in two thirds of the cases. Squamous cell changes, in the vicinity of the primary adenocarcinoma, are present in 27% of cases. The carcinoma is in a pathologically advanced stage in one third of the cases. Colectomy is the main therapeutic modality. Survival following surgical resection ranged from 7 months to 21 years. We present an additional case of rectal squamous cell carcinoma (SCC) complicating chronic ulcerative colitis in a 33-year-old woman who had the disease for 15 years. Multiple biopsies of a gross lesion located 5 cm above the dendate line were consistent with invasive basaloid cell carcinoma. The patient received 5-FU, mitomycin C, and radiotherapy prior to a proctocolectomy and ileostomy. The only histopathologic finding at pathologic review of the surgical specimen was severe squamous dysplasia.