Medullary thyroid carcinoma and pregnancy

Medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor of the parafollicular cells of the thyroid gland. The tumor occurs, either sporadically or in a hereditary form, as a component of the type 2 multiple endocrine neoplasia (MEN) syndromes, MEN2A and MEN2B, both with an autosomal dominant transmission. Due to its higher aggressiveness and urgency to treat, it poses a challenge when diagnosed during pregnancy. We performed a literature review searching medical databases as UpToDate and PubMed for relevant information about diagnosis, impact, treatment, and outcome of medullary thyroid carcinoma during pregnancy. Diagnosis of MTC is established by clinical and ultrasound evaluation, followed by a fine needle aspiration biopsy. Further analyses decide whether it is a sporadic or a hereditary disease. Surgery offers the curative solution, but careful postoperative follow-up is needed for the best outcome. The decision for surgery is taken considering the DNA mutation of RET oncogene and pregnancy status. A premature planned delivery is associated with potential complications for the newborn, but it is recommended when maternal status worsens. Conclusions. Complete resection of the thyroid tumor and any local and regional metastases is the only curative solution. Timing of the intervention is extremely important to decrease fetal outcomes. Close follow-up during the postoperative period, by both biochemical and imaging methods, is needed.