TSH (thyroid-stimulating hormone)-secreting
tumors are the rarest type of
pituitary tumor. The objective of this study was to describe initial presentation and follow-up in patients presenting TSH-secreting
tumors and to characterize the pathological features, based on a cohort of 20 patients treated in our referral center, between 1981 and 2014. Most of the patients (75%) were female, aged around 50 years (mean: 50±13 years). Initial symptoms were
hyperthyroidism (8/20) and/or
tumor mass-related symptoms. Median time to diagnosis was 18 months. Biochemical
hyperthyroidism was found in 15 patients. Most of the
tumors were macroadenomas (75%) and 30% were invasive. Seventeen patients underwent transsphenoidal surgery. All
tumors expressed TSH, with>50% positive cells. Eleven were monohormonal and 6 plurihormonal, expressing βTSH plus
growth hormone (GH) and/or
prolactin (PRL). Both subtypes showed high expression of Pit-1 and
SSTR2A somatostatin receptors. SSTR5 was slightly expressed in the plurihormonal subtype. Ki-67 index was elevated (≥3%) in only one
tumor. Signs of
hyperthyroidism were more frequent in the plurihormonal than in the monohormonal subtype. At final follow-up (median: 34.79±66.7 months), 75% of the patients were
in complete remission after surgery; persistent
hyperthyroidism was controlled by
somatostatin analogs, alone (n=3) or associated to
radiotherapy (n=1). The multidisciplinary approach promoted early diagnosis and control of
hyperthyroidism by neurosurgical treatment, associated to
somatostatin analogs or not. Clinical/pathological correlations highlighted the variations in immune profiles and in clinical and biological symptoms.