Metachronous metastasis of papillary thyroid carcinoma to the parotid gland: a case report and review of the literature

Background: We present a case of metachronous metastasis of papillary thyroid carcinoma to the parotid gland, this being an extremely rare metastasis, and a literature review.

Case report: A 56-year-old female patient presented with a history of a slowly growing mass on the left side of the neck. The patient reported a medical history of thyroidectomy due to papillary thyroid carcinoma 23 years previously and neck dissection for lymph node metastases 10 years previously, with additional therapy using radioactive iodine in both cases. Computed tomography (CT) of the neck revealed a single nodular solid mass in the tail of the left parotid gland which showed heterogeneous intake of contrast agent. FNA biopsy of the left parotid gland revealed cells typical of papillary thyroid carcinoma with positive immunochemistry for TTF-1. Due to this new metastasis, a total parotidectomy with preservation of the facial nerve was performed and additional therapy with radioactive iodine was administered.

Conclusion: Despite the fact that papillary thyroid carcinoma has a low incidence of regional and distant metastases, there are a few rare cases with distant metastases reported in the literature. Thus, awareness, especially among endocrinologists, and a multidisciplinary approach are crucial to ensure early detection and efficient treatment of these rare cases, distant metastases being the main cause of mortality and of reduction of overall survival rate among these patients.