Diagnosis, pathology, and management of TSH-secreting pituitary tumors. A single-center retrospective study of 20 patients from 1981 to 2014

AbstractTSH (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 SSTR 2A somatostatin receptors. SSTR 5 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.