Sporadic and Familial Medullary Thyroid Carcinoma: A Retrospective Single Center Study on Presentation and Outcome.

Background: Medullary Thyroid Carcinoma (MTC) is a neuroendocrine tumor that arises from the thyroid C-cells. Most cases are sporadic (sMTC) while, approximately 25%, are hereditary (hMTC) due to germline mutations of REarranged during Transfection (RET) gene mutations and manifest in the framework of multiple endocrine neoplasia (MEN) 2A or 2B, or as pure familial MTC syndrome (FMTC).

Objective: The aim of this study is to evaluate the clinical, histopathological, biochemical and outcome differences between sMTC and hMTC.

Methods: Retrospective analysis of a consecutive series of 102 patients with histologically proven MTC diagnosed in the period between 2000 and 2022. For the analysis patients with MTC diagnosed during screening through genetic test were excluded.

Results: Patients with hMTC had higher incidence of multifocal and bilateral MTC and younger age at diagnosis. We did not found differences on tumor stage at diagnosis between sMTC and hMTC, such as time to progression and rate of persistent and recurrent disease. At univariate analysis, factors associated with persistent and recurrent disease during follow-up in patients with sMTC were tumor size, extrathyroidal extension, presence of lymph node metastases at diagnosis, pre- and post-operative calcitonin, post-operative CEA; in patients with hMTC, features associated with persistent and recurrent disease were lymph node metastases, post-operative calcitonin and pre- and post-operative CEA values.

Conclusion: Patients with hMTC and sMTC had similar histopathological characteristics and clinical outcome.