Leiomyomas of the rectum and anal canal: report of six cases and review of the literature.

Since 1872, 168 rectal leiomyomas have been reported in the world literature. Their incidence, therefore, is very low. It is estimated that one leiomyoma may be seen for every 2,000 or more rectal tumors. Those leiomyomas located in the anal canal and sphincter are the rarest. A case is reported here that appears to be the eleventh in such a location. The incidence of these lesions is highest between the ages of 40 and 59 years. Most patients have a combination of symptoms rather than a single one, the most frequent of these being the presence of a mass, bleeding, and constipation. Almost always, the chain of events that leads to the diagnosis starts when the tumor is discovered by digital examination of the rectum. The lack of reliable criteria of malignancy and the marked tendency to recur shown by these tumors are the two main problems the surgeon faces when selecting the operative procedure to be used. We believe that those tumors with an original size of 5 cm or more in largest diameter are the ones that have shown the highest tendency to recur, mostly as sarcomas. Therefore it is thought that these lesions should be treated radically from the beginning, especially when they recur. More adequate follow-up studies are needed.