Cribriform variant papillary thyroid cancer: a characteristic of familial adenomatous polyposis.

Inherited cancer syndromes may predispose to more than one type of cancer, and these characteristically develop at an earlier age than their sporadic counterparts. The occurrence in a single individual of multiple, early onset primary cancers may indicate an inherited cancer susceptibility. Familial adenomatous polyposis (FAP), an autosomal, dominantly inherited susceptibility to colorectal adenomas and cancer also predisposes to childhood medulloblastomas and to a specific rare histologic type (cribriform variant) of papillary thyroid cancer. We describe a patient who developed a childhood medulloblastoma of the cerebellum, and subsequently a cribriform papillary thyroid cancer. These cancers predated the diagnosis of FAP in this patient, who was later found to have several relatives with FAP. The adenomatous polyposis coli (APC) mutation delineated in this family was in the region associated with those causing an increased risk of thyroid cancer. We submit that the diagnosis of the cribriform variant of papillary thyroid cancer in a young individual, especially after a previous cancer diagnosis, should alert the physician to the possibility of a diagnosis of FAP.