Familial occurrence of medullary thyroid cancer is well known in families as an isolated malignancy or in association with multiple endocrine neoplasia syndrome type II. Conversely, papillary thyroid cancer almost always presents sporadically except for reports of familial clustering in individuals with radiation exposure, inherited syndromes of colonic polyposis or multiple harmatomas, and rarely in monozygotic twins. We report a case of papillary thyroid cancer diagnosed incidentally in a 53-year-old woman who underwent surgery for excision of an adenomatous nodule. It was noted that her mother suffered from a similar thyroid malignancy some 33 years ago, and several of her maternal relatives had either Graves' disease or hypothyroidism. The possible existence of this familial entity and its likely genetic basis is discussed.