Endocrine Abstracts

Introduction: At the time of diagnosis of medullary thyroid carcinoma (MTC) 10 to 15% of patients have distant metastases, 25% of them develop them over a longer or shorter period of time. The usual metastases concern cervical lymphadenopathy, bone, lung and liver. There are also unusual secondary localisations. We report a case.

Observation: A 56-year-old patient who consulted a year after apparition of cervical lymphadenopathy, whose fine needle aspiration returned in favor of a MTC with serum thyrocalcitonin (TCT) level at 2000 pg/l. The extension assessment was negative, the patient was operated on and the anatomopathological study confirmed the diagnosis of MTC classified as PT3N1bM0. The genetic study of the RET mutation could not be carried out. 6 weeks after surgery the TCT level returns to 1500 pg/l. At 3 months after surgery, the patient presented with inguinal lymphadenopathy, the fine needle aspiration of which revealed a carcinomatous process with a TCT level in the liquid washing was 2342 pg/l. the serum TCT level returned to 3789 pg/l, and the extension assessment found a right adrenal metastasis of 14mm (the diagnosis of pheochromocytoma was ruled out), multiple right femoral and vertebral bone metastases with spinal cord compression of L1, the latter’s surgery is rejected, so he benefits from decompression radiotherapy. The patient is put on vandetanib

Discussion: The rapid evolution in our patient with the appearance of multiple metastases, two of which are unusual in 2 months, raises fears of a codon 918 mutation of the RET proto-oncogene. Few studies specify the proportion of rare localizations of MTC; one study of 19 patients reported 10% adrenal and digestive metastases, while another of 35 patients found no cases. In our reading we found only two described cases of metastatic inguinal lymphadenopathy.

Conclusion: Metastases from unusual locations do not seem so rare, they must be sought in the event of a doubling of TST values and be treated in patients whose survival is sometimes very prolonged.