Syndrome of precocious menstruation and galactorrhea in juvenile hypothyroidism: an example of hormonal overlap in pituitary feedback

Summary 

A syndrome associated with juvenile hypothyroidism is described, the cardinal feature of which is sexual development beyond that consistent with the bone age and other indices of maturity. The 3 girls described in this paper had precocious menstruation, galactorrhea, absence of public hair, and enlargement of the sella turcica. One patient was excessively pigmented. These abnormal signs disappeared promptly when the hypothyroid state was alleviated. Serial x-rays of the skull after treatment with thyroid was instituted revealed an initial period of further enlargement and demineralization of the pituitary fossa followed by a decrease in its size toward normal. A normal menarche later ensued in 2 of the girls when the level of maturity had progressed appropriately. The implications of the close similarity between the findings in this syndrome and in patients with pituitary tumors are discussed. A primary target gland deficiency is suggested as the etiologic factor in at least some patients with chromophobe adenomas.

It is postulated that the mechanism for the development of menorrhagia, galactorrhea, and pigmentation in these patients was an overlapping secretion of gonadotropin, mammotropic hormone, and (in 1 case) melanocyte-stimulating hormone along with the presumed high level of thyroid-stimulating hormone. A similar overlap in pituitary hormones occurs in experimental pituitary tumors induced by single target gland deficiencies and in certain clinical endocrine disorders. This lack of specificity in the pituitary feedback mechanism, so strikingly demonstrated in the present syndrome, is suggested as the mechanism responsible for a number of phenomena commonly observed in clinical endocrine disorders.

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