New phenotypic aspects in a family with Lynch syndrome II.

Increasing attention has been given to hereditary nonpolyposis colorectal cancer (HNPCC). This report provides medical genetic/pathologic findings on an HNPCC kindred from southern Italy that shows criteria consistent with Lynch syndrome II. An international collaborative effort led to extension of this kindred with disclosure of a potentially new spectrum of phenotypic findings: an excess of gastric carcinoma; complete intestinal metaplasia and chronic atrophic gastritis restricted to the antrum; an apparent excess of colonic mucosal macrophagia, which by special stain appeared to be positive for mucin, with a constant content of both sialo and sulfomucin, a lack of iron, and an inconstant positivity for lysozyme obtained by immunoperoxidase technique; and findings of crypt atrophy of the colonic mucosa. During the relatively short period of investigation of this family, an intensive educational and surveillance program has been mounted in the interest of improving cancer control through direct application of knowledge of natural history and the risk factor evidence through pedigree assessment.