Two Families with an Autosomal Dominant Inheritance Pattern for Papillary Carcinoma of the Thyroid

Background: Papillary carcinoma of the thyroid (PTC) is the most prevalent malignancy of the thyroid gland. Although the majority of lesions are sporadic tumors, an established relationship exists between familial adenomatous polyposis (FAP) and PTC. Moreover, some authors postulate the existence of familial PTC as a distinct entity. Evidence for this is limited, however, there being few well characterized descriptions of pedigrees with high prevalence of PTC. Aims: The objective of the present study was to examine an apparent heritable predisposition to PTC occurring in two Tasmanian families in which PTC occurs commonly. Methods: Pedigree charts were constructed for both families and the medical records of the members reviewed. Results: In Pedigree I, 7 of 25 members had PTC (6 of these had coexisting multinodular goiter (MNG), and 11 others had MNG. In Pedigree II, identical male twins and their daughters had PTC. Conclusions: In both families there is evidence of autosomal dominant inheritance of PTC. The association of PTC with MNG suggests a possible role for MNG in tumor pathogenesis in hereditary PTC. The majority of the patients were diagnosed with PTC before commencement of prospective screening, indicating clinically relevant disease in the families described.