Normal Thyroid Pathology in Patients Undergoing Thyroidectomy for Finding a RETgene Germline Mutation: A Report of Three Cases and Review of the Literature

Genetic screening for germline RET proto-oncogene mutation in hereditary medullary thyroid cancer (MTC) is accurate and allows for preventive total thyroidectomy to be performed early in patients who are gene carriers. We report 3 children who underwent preventive total thyroidectomy based on the finding of a RETgene germline mutation, but who had no evidence of MTC or C-cell hyperplasia on permanent histology, even after calcitonin immunostaining. Review of the English literature of patients undergoing preventive thyroidectomy for a positive RETgene germline mutation, shows that 3.4% of these patients (a total of 209 patients) had normal thyroid glands. Also, 8.6% of patients undergoing preventive total thyroidectomy with prophylactic central neck node dissection had cervical node metastases. We conclude that preventive thyroidectomy in patients screened early for germline RETgene mutation allows for earlier diagnosis and treatment of patients, sometimes even before any hyperplasia or neoplasia can be demonstrated because cervical node metastases can occur early and be demonstrated even with small tumors (< 1 cm), we recommend prophylactic central neck node dissection at the time of preventive thyroidectomy.