The clinical spectrum of TSH-expressing pituitary adenomas

Abstract

Background: Thyroid-stimulating hormone (TSH)-expressing pituitary adenomas are a rare but important entity with a spectrum of clinical manifestations. Here, we report our experience with managing TSH-expressing pituitary adenomas over eleven years – the largest single-centre data published to date. Methods: We reviewed retrospectively all patients with histopathologically-proven TSH-expressing pituitary adenomas presenting to our centre between 2002 and 2012 inclusive. Data were obtained on clinical presentation, biochemical status, tumour size, management, histopathological results, and long-term outcomes. Results: 32 patients (16 males) were identified. Mean age at presentation was 52.9 years, and mean follow-up was 79 months. Visual disturbance was the commonest presenting complaint in 34%, and 25% of the patients were clinically hyperthyroid at presentation. 84% of the patients had plurihormonal pituitary adenomas. All patients initially underwent transsphenoidal surgery, one underwent post-operative radiotherapy. 31% (10) patients had recurrence; two of these had an empty pituitary fossa on initial post-operative imaging. One patient died, from an indirect cause. The clinically active and silent tumours (defined by the presence or absence of clinical hyperthyroidism, respectively) behaved in a similar manner, including with respect to recurrence rates. Conclusions: TSH-expressing pituitary adenomas have a wide clinical spectrum. Patients are often clinically euthyroid but may have signs or symptoms of derangements in other pituitary hormones. Visual disturbance is common. Despite radiological evidence of clearance following surgery, and extended follow-up, TSH-expressing pituitary adenomas may still recur. Our data supports the need for close long-term follow-up of such patients, and supports the notion that the clinically silent tumours are not a benign entity.