peer reviewed ; OBJECTIVE: Our aim was to report the recent changes in diagnosis and management of TSH-secreting pituitary adenomas. METHODS: We retrieved 43 consecutive patients with TSH-secreting pituitary tumors (23 male and 20 female) among 4400 pituitary adenomas followed between 1976 and 2001 in six Belgian and French centers. RESULTS: TSH was elevated in 18/43 and alpha subunit in 13/32 patients. In patients with intact thyroid (n=30), mean free tri-iodothyronine was 13.1 pmol/l (range 3.5-23) and mean free thyroxine was 38.4 pmol/l (range 10.2-62.7). Hyperprolactinemia and acromegaly were associated in 9/43 and 8/43 cases. The number of associated hypersecretions was higher in macroadenomas than in microadenomas (Chi square = 11.2, P<0.01). Two women had sporadic multiple endocrine neoplasia type 1-associated syndrome. The proportion of microadenomas versus macroadenomas was 1/11 (period 1974-1986) and 8/32 (period 1987-2001). Bilateral petrosal sinus sampling, (111)In-pentreotide scintigraphy and ((11)C)-l-methionine positron emission tomography scan confirmed diagnosis in four questionable microadenomas. Macroadenomas with extrasellar extension (31 cases) had a tendency to be medially located. Medical treatment with somatostatin analogs was initiated as first-line treatment in 26 patients. TSH levels were reduced by more than 50% in 23/26 cases. A tumoral shrinkage of more than 20% was observed in 5/13 cases. Surgery was performed in 36 patients. After 1 year, 21 of them (58.3%) met the criteria of surgical favorable outcome. Pituitary radiotherapy (n=8) and somatostatin analogs allowed normalization in cases not cured by surgery. CONCLUSION: Ultrasensitive methods for TSH measurement led to an earlier recognition of TSH-secreting pituitary tumors. In this series, we observed that TSH-secreting pituitary tumors are today more frequently found at the stage of microadenomas, medially located, without associated hypersecretions and needing new exploration methods as compared with older series. This ...