A unique case of benign pleomorphic adenoma metastasizing to the thyroid gland and liver

Abstract

A recurrent benign metastasizing pleomorphic salivary adenoma (PSA) is extremely rare occurring in less than 1% of patients. There are approximately 50 cases that have been reported in the literature but none with metastases to the thyroid gland. We report a case of a 68-year-old lady who was initially investigated for a space-occupying lesion in the liver but was found to have metastases in the thyroid and liver as well as recurrence of the parotid primary. The clinical findings, management, and a review of the current literature are reported. Metastases from PSAs are extraordinary. We describe the first reported metastasis from the parotid to the thyroid gland. In this case, we report an excellent outcome post-operatively and argue for the benefit of long-term follow-up.