Squamous cell carcinoma of the anus in a patient with perianal Crohn’s disease

Dear Editor Anal cancer is a rare disease and accounts for approximately 1.86% of all carcinomas originating in the digestive system. The American Cancer Society estimates that in 2008, there will be 5,070 new cases of anal cancer and 680 deaths from anal cancer in the USA. Anal cancer arising in patients with Crohn’s disease is also rare. The incidence or prevalence of anal carcinoma in Crohn’s disease is not sufficiently reported. According to Slater et al., the percentage of anal cancer in colorectal cancer in patients with Crohn’s disease is higher than that in patients with non-inflammatory bowel disease (IBD; 14% versus 1.4%, respectively, p<0.005). On the other hand, Frisch et al. reported one case of anal squamous cell carcinoma (SCC) among 2,723 Crohn’s patients with a median follow-up of 10.2 years and concluded that the rate of anal SCC is not significantly increased, even in IBD patients, as compared with the general population. Incidence rates of IBD diverge geographically. Traditionally, Northern Europe, the UK, and North America have a high prevalence of IBD. The incidence and prevalence rates of IBD in Asia are low compared with the West. According to a recently published epidemiologic study by Thia et al., incidence rates of Crohn’s disease in Japan, South Korea, and Hong Kong are similar, ranging from 1.00 to 1.34 cases per 10 person-years over a combined time period from 1998 to 2005, and interestingly, the incidence of Crohn’s disease is increasing in these areas. Approximately 40 cases of carcinoma that developed from anal lesions or in association with anal or rectal fistulas arising in patients with Crohn’s disease were reported in English literature from 1980 to 2008. Most of these cases were reported from Northern Europe or North America, and as far as we know, reports from East Asia are very rare. Our hospital is a tertiary referral center in South Korea. From 1991 to 2008, 843 patients were treated for IBD. We report the first case of SCC arising in a patient with perianal Crohn’s disease in our hospital. A 43-year-old woman had an 11-year history of Crohn’s disease. She underwent large loop excision of the transformation zone due to cervical cancer (carcinoma in situ) in 1997. Despite regular follow-up with sulfasalazin, steroid, or intermittent infliximab treatment, the patient developed enteroenteric fistulas as well as an anal stricture and multiple perianal fistulas. Even though the patient received conservative medical treatment, a small-bowel fistula did not resolve, and the patient suffered an increasing frequency of low abdominal pain with an engrowing palpable mass in the right lower abdomen. She underwent laparoscopic assisted right hemicolectomy, segmental resection of the small bowel, end ileostomy, and seton drainage for the rectovaginal fistula in January 2008. Fecal diversion was performed to relieve the perianal discomfort induced by J. Kang : B. S. Min :K. Y. Lee :N. K. Kim (*) Department of Surgery, Yonsei University Health System, Yonsei University College of Medicine, 250 Seongsanno (134 Sinchon-dong), Seodaemun-gu, Seoul, South Korea 120-752 e-mail: namkyuk@yuhs.ac