Smooth-muscle rectal tumors: a therapeutic dilemma.

Five cases of smooth-muscle rectal tumors seen in the Lexington, Kentucky, area over a 25-year period are reported. These unusual tumors cause symptoms similar to those of more common anorectal diseases, namely, painful defecation and rectal bleeding. Often these tumors are initially asymptomatic due to their submucosal origin. Clinical diagnosis depends on awareness of these lesions, digital rectal examination, endoscopic examination, and tissue biopsy. Microscopic diagnosis and differentiation of malignant from benign features require a pathologist with special interest and expertise with these lesions. Smooth-muscle rectal tumors should be considered more dangerous than those in other locations in the gastrointestinal tract, as half are malignant and only a fifth of patients who have sarcomas survive five years. Treatment of malignant rectal myomas should be very aggressive from the outset, with abdominoperineal resection being advocated by most investigators due to almost uniform local recurrence with lesser procedures. When the lesion recurs, it is likely to be more virulent histologically and clinically than the initial lesion. Benign myomas are cured by local excision alone.