The protean manifestations of familial polyposis coli.

Although familial polyposis coli (FPC) is often thought to be a discrete disease with uniform clinical presentation and few therapeutic options, review of 16 families encountered in the last five years has shown that marked variation in the clinical manifestations of the syndrome is the rule rather than the exception. Thirty one percent of propositi had negative family histories, 67 percent of observed cancers were in the rectum, three individuals from three families developed cancer under the age of 20. In another family the only cancer was in a 67-year-old patient. Polyp growth rate varied tremendously among individuals and over time within individuals, rectal polyps did not regress after subtotal colectomy, and three patients developed rectal cancer after subtotal colectomy (18 percent). Fifty percent of propositi had cancer on presentation, while only 18 percent of screened family members had cancer. The only extracolonic tumors seen were gastroduodenal polyps and retroperitoneal desmoids in three families. The mode of inheritance of FPC causes this variation and treatment is best tailored to the individual and his family rather than uniformly applied to all patients with FPC.