Anal neoplasms.

A common theme in most anal neoplasms appears to be a delay in diagnosis due to confusion with more common, benign conditions. Thus, the clinician must maintain a high index of suspicion when evaluating lesions of the anal canal and margin. The use of primary chemoradiation for SCC of the anal canal has resulted in equivalent, if not superior, local control and survival compared with radical surgery, and results in sphincter preservation in over two thirds of cases. Nevertheless, abdominoperineal resection still plays an important role in salvage of treatment failures, and also for patients who are unlikely to tolerate chemoradiation or have pre-existing impaired continence. Recent studies indicate that variations in chemotherapeutic agents and radiation technique might potentially produce even better results. The prognosis for anorectal melanoma, as well as for small cell and undifferentiated tumors, continues to be poor. Fortunately, these are relatively rare tumors.