%0 Journal Article %A H. B. Lee %A C. Faiman %T Isolated thyrotropin deficiency due to a pituitary tumour %D 1977 %J Canadian Medical Association Journal %P 520-521 %V 116 %N 5 %X Hypothyroidism due to isolated deficiency of thyrotropin (TSH) associated with an enlarged sella turcica, presumably the result of a nonfunctioning pituitary adenoma, occurred in a 58-year-old man. Low serum concentrations of TSH and thyroid hormones, together with the lack of TSH response to administration of thyroid releasing hormone, indicated a pituitary deficiency of TSH. Serum values of other pituitary hormones were normal. %U