[Hyperthyroidism associated with hydatid moles]

With reference to a 25-year-old patient who developed manifestations of clinical and paraclinical hyperthyroidism during the course of a molar pregnancy, the authors studied correlations between the two conditions. Hyperthyroidism is the result of hyperstimulation, of placental origin, and disappears when the hyperstimulation disappears. The placenta is capable of producing a TSH-like factor. HENNEN and HERSCHMAN established the existence of human chorionic thyrotropin which has hormonal and physicochemical properties similar to those of TSH, and which has just been isolated by Japanese workers. In fact during the development of a mole, it is molar HCT (or MHCT) that constitutes either a precursor or a subunit of HCT. However, hyperthyroidism remains rare during the course of molar pregnancies, a fact that has not yet been explained.