[Transient diabetes insipidus following removal of a medullary thyroid carcinoma (author's transl)].

Medullary thyroid carcinoma (MTC) is a known apudoma producing calcitonin, prostaglandins and serotonin. It can present itself as a familial or sporadic form or as part of a multiple endocrine adenomatosis. We present here the case of a patient admitted with a four-year history of diarrhea, enlargement of the thyroid and palpable lymph nodes in the right side of the neck. There was no uptake of 131I in the right lobe of the thyroid and the serum calcitonin levels were very high. With the diagnosis of MTC a total thyroidectomy mas performed developping within hours of the surgical procedure a picture of diabetes insipidus with 31 liters of urine output in the first 48 hours. It responded to vasopressin and disappeared spontaneously in two weeks. We have considered the different mechanisms that could explain the development of diabetes insipidus, and after failing to find one, we especulate at prostaglandins could play an important role in the synthesis and/or release of ADH. The sudden depletion of prostaglandins after removal of the neoplasm that produced them could account for the diabetes insipidus in our patient. We have not found any similar case described in the literature. We call attention to the need for a close postoperative observation of patients operated for MTC for the possible onset of diabetes insipidus.