Comprehensive evaluation of thyrotropinomas: single-center 20-year experience

To present a single-center 20-year experience with operated thyrotropinomas, including prevalence, clinical, biochemical and histological characteristics, and postoperative outcomes.

Retrospective series of histopathologically-proven thyrotropinomas (1993-2013), divided in two groups: A (active, central hyperthyroidism) and B (silent, no hyperthyroidism).

Of 1628 operated pituitary adenomas, 20 were β-TSH-positive (1.2%). In increments of 5 years, proportion of thyrotropinomas was 1, 1, 0.04 and 1.77% respectively. Median follow-up was 10.4 months (1.2-150). Group A: 6 patients (5 men), age 41 ± 12 years presented with hyperthyroidism (3), pituitary incidentaloma (2) and acromegaly (1). Tumor diameter was 2.1 ± 1.2 cm, FT4 2.68 ± 2.73 ng/dL; TSH 6.50 ± 3.68 µIU/mL. Glycoprotein alpha subunit (GSU) was uniformly elevated. Two patients had biochemical evidence of acromegaly. Tumors were plurihormonal (5 GH-positive); none atypical. Postoperative euthyroidism was achieved in 4 of 6 patients (66%). Group B: 14 patients (7 men), age 47 ± 14 years presented with acromegaly (6), mass effect (4), incidentaloma (3) and galactorrhea (1). Tumor diameter was 2.0 ± 1.0 cm. Free T4 (1.00 ± 0.24 ng/dL) and TSH (2.02 ± 1.65 mIU/L) were lower than in group A (p < 0.01). GSU was elevated in all tested cases. Nine patients had biochemical evidence of acromegaly. Tumors were plurihormonal (12 GH-positive); none atypical. Gross total resection was achieved in 12 of 14 (86%), and 1 (7%) recurred.

In our series, more thyrotropinomas were operated in recent years. These tumors were often plurihormonal with heterogenous clinical presentation and frequent GH co-secretion. Surgical outcomes were good but long-term follow up is necessary.