Endocrine Abstracts

Background: Medullary and papillary thyroid carcinomas are distinct entities, regarding their incidence, cellular and genetic origin, histopathological features and prognosis, but there have been described a few cases of the two occurring simultaneously in the same patient. Medullary thyroid carcinoma represents between 1–5% of all thyroid malignancies and it is responsible for 12–13% of all cancer related deaths. The familial form (10–20% of the cases) is caused by a RET protooncogene germline mutation and it can also be found in multiple endocrine neoplasia patterns (2A and 2B). Medullary carcinoma arises from the C-parafollicular cells and it usually metastasize to cervical lymphatic nodes and surrounding tissues. The therapeutic approach should always include total thyroidectomy, lymphadenectomy and genetic testing for RET mutations.

Case presentation: We will report the case of a 35 year old female patient with family history of medullary thyroid carcinoma, who has tested positive for RET protooncogene mutation. Patient had no symptoms, serum calcitonin was elevated preoperative and neck ultrasound showed a hypoechogenyc, unprecise delimited area of 3/3 mm in the left thyroid lobe. She underwent prophylactic total thyroidectomy and histopathology examination showed presence of both medullary bilateral microcarcinoma and papillary microcarcinoma, follicular variant. We will also present the genealogical tree of the RET mutation in the patient’s family along with some distinctive details of their disease.

Conclusion: We reported a case with a rare finding, coexistence medullary and papillary carcinoma of the thyroid, in a patient with family history of medullary carcinoma of the thyroid with RET protooncogene mutation.