Familial papillary thyroid microcarcinoma: a new clinical entity

Background Familial, non-medullary thyroid carcinoma is clinically more aggressive than the sporadic form. We wanted to find out whether papillary thyroid microcarcinoma also occurs in a familial pattern, and, if so, to identify specific clinical and prognostic features. Methods We reviewed the clinical records of 119 patients with papillary thyroid microcarcinoma. Familial occurrence, together with clinical presentation, surgical treatment, pathological characteristics, and follow-up were recorded. Findings We identified a family history of thyroid carcinoma in seven patients. The tumour was multifocal in five patients, bilateral in three, and vascular invasion occurred in three of the seven patients. Lymph-node metastases were found in four patients. Three patients had a recurrence and one patient with pulmonary metastases died within 11 months. Interpretation We identified familial occurrence in 5·9% of cases of papillary thyroid microcarcinoma. The unfavourable behaviour in the familal form of papillary thyroid microcarcinoma suggests that radical treatment and careful follow-up are warranted.