Medical aspects of hereditary intestinal polyposis.

Extracolonic manifestations are often associated with familial polyposis coli, but the cysts and osteomas may be few and inconspicuous. Abnormal fibrous reactions may also occur and may be a cause of death. These manifestations act as "external markers" for the later appearances of adenomas. In any family, some individuals may manifest some extracolonic manifestations and other individuals may not. Other abnormalities, usually neoplastic, described in familial polyposis coli families, are probably fortuitous occurrences, but medulloblastoma has been found relatively frequently. Turcot's syndrome, described in a unique family, should be used more restrictively. Diagnosis depends on histology showing adenomas, but no particular number is required in an afflicted family member. Total reliance on sigmoidoscopy alone is potentially hazardous as the descending colon may be affected initially. Inherent problems regarding "isolated cases" are outlined.