Endocrine Abstracts

Introduction

MEN 2A is an autosomal dominant disease, a familial syndrome with a mutation at RET proto-oncogene. %25 of medullary thyroid carcinoma (MTC) is a part of MEN 2A. Herein, we presented a patient with MEN 2A who was found to be heterozygos for RET mutation cause of the association of MTC and papillary thyroid carcinoma (PTC) is very rare.

Case

63 year old patient was admitted to the endocrinology clinic after total thyroidectomy as the thyroid tissue contains both MTC and PTC focuses in each thyroid lobe. As there was family history of MEN syndrome, the patient was evaluated for MEN syndrome. Abdominal MRI revealed a mass in the left adrenal, 28×23 mm in size, showing heterogeneous signal loss in the external phase sequence, and heterogeneously enhanced pheochromocytoma in the arterial phase. The dopamin level in the 24 hour urine collection measured at two different occasions were 442.91 and 536.98 µg/day (65–400) respectively. The level of calcium, phosphorus and parathyroid hormone (PTH) were normal. On postop neck USG, an appearance compatible with residual throid tissue with dimensions of 22×15 mm in the localization of the left throid gland was detected. Calcitonin level was 33.6 pg/ml (<8.4). Thyroglobulin level was <0.1 mcg/l (1.15–50.03), anti-thyroglobulin level was < 0.9 IU/ml (0–4). One alelle (heterozygous) had c.23706>T(P.L790F) due to RET mutation. With these results, the patient was evaluated as MEN 2A. Left adrenalectomy and reoperation of residual thyroid tissue were recommended. Patient wanted to go another center for surgery.

Conclusion

The other components of MEN 2A should be investigated for all patients diagnosed with MTC. Family screening, serum calcitonin level, neck USG, existence of RET mutation and biochemical panel for pheochromocytoma should be investigated. Coexistence of MTC and PTC is very rare. There is no sufficient data to prove this association. However, it is assumed that the RET proto-oncogene would lead to the thyroid kinase activation.