Is familial papillary thyroid carcinoma different from sporadic form in terms of clinicopathological features and outcome?

Objective: Familial papillary thyroid cancer (FPTC) is an uncommon and not well-defined clinical entity. Although some studies report more aggressive characteristics in FPTC, others do not favor these findings. This study aimed to analyze the ultrasonographic and cyto-histopathological features of patients with FPTC and sporadic papillary thyroid cancer (SPTC). Methods: The data of 292 patients diagnosed with PTC histopathologically between 2007 and 2018 were retrospectively reviewed; and their thyroid function tests, ultrasonographic properties, and cyto-histopathological results were compared. Results: We analyzed 132 tumor foci in 69 patients with FPTC and 322 foci in 223 patients with SPTC. Sex distribution, rate of thyroid auto-antibody positivity, and median nodule number were similar in the 2 groups. In preoperative ultrasonographic (US) examination of malignant nodules, the mean nodule diameter was smaller, microcalcification was lower, and isoechogenity were higher in patients with FPTC than in those with SPTC (p=0.001, p=0.005, p=0.0.025, respectively). Cytological results were distributed similarly (p=0.100). Multifocality was higher in patients with FPTC (47.8% vs 30.9%, p=0.009). The median tumor diameters, rate of microcarcinoma, distribution of PTC variants, extracapsular extension, and vascular invasion were comparable. Capsular invasion and regional nodal metastasis were significantly increased in the SPTC group (17.4% vs 9.1%, p=0.024 and 13.0% vs 2.9%, p=0.018; respectively). Although stimulated thyroglobulin levels at the 6th month were higher in the sporadic group, the conventional and dynamic responses were similar in both groups. Conclusion: Whether FPTC is more aggressive than SPTC is debatable. We found a higher rate of multifocality, but a lower rate of lymph node metastasis in FPTC. The prognosis was similar in patients with FPTC and SPTC. Early detection might lead to an early diagnosis in the familial form of the disease.