Seven Cases of Anal Carcinoma Associated with Anal Fistula

We studied 7 cases of anal carcinoma associated with anal fistula, which were treated in our institute from January 1970 to September 1991. The patients consisted of 6 men and one woman with an average age of 59.1 years ranging from 43 to 77 years. The period from the onset of anal fistula to the diagnosis of carcinoma ranged from 4 to 47 years with a mean of 22.9 years. Their chief complaints were anal mucinous discharge and/or bleeding, anal pain, palpitation of perianal hard nodules and anal stenosis. All patients were treated by abdominoperineal resection consisting of 4 curative and 3 non-curative resections. Histological findings varied, with 3 mucinous and 3 well/moderately differentiated adenocarcinomas and one squamous cell carcinoma. Although 4 of the 7 cases were diagnosed at the first diagnostic trial, the repeated biopsies failed to reveal the cancer cells in the other 3 cases until the final diagnosis. We concluded that repeated diagnostic trials including extended excision of the fistula are required for patients who have a long history of anal fistula with mucinous discharge and hard nodules, to differentiate the onset of anal carcinoma.