TOPLINE:

Patients with pituitary thyroid-stimulating hormone (TSH)-secreting adenomas had markedly lower bone mineral density (BMD) across multiple skeletal sites than matched control individuals with normal thyroid function. After complete surgical resection of the tumor, levels of bone turnover markers decreased, and BMD stabilized but without significant recovery.

METHODOLOGY:

• TSH-secreting adenomas cause elevated levels of thyroid hormones in the presence of unsuppressed TSH levels, with the two factors exerting opposing effects on bone. While elevated levels of thyroid hormones accelerate bone resorption, unsuppressed TSH has protective effects on bone. Delayed diagnosis of these adenomas can lead to chronic bone mass loss and fractures, and the net effect remains uncertain.
• Researchers conducted a retrospective analysis to compare BMD and levels of bone turnover markers between patients with TSH-secreting adenomas and euthyroid control individuals and to evaluate the effect of surgical treatment on bone metabolism.
• Overall, 71 patients (mean age, 43 years; 67.6% women) who underwent surgical resection of TSH-secreting adenomas and had BMD data available were matched with 71 control individuals with normal thyroid function; 13 patients with pre- and postoperative BMD data were included in a longitudinal evaluation of surgical effects on bone status.
• BMD was assessed at the lumbar spine (L1-4), femoral neck, and total hip, with levels of bone turnover markers including alkaline phosphatase (ALP), C-terminal telopeptide of type 1 collagen (B-CTX), and procollagen type 1 N-terminal propeptide (P1NP) measured.

TAKEAWAY:

• Compared with euthyroid control individuals, patients with TSH-secreting adenomas had significantly reduced mean BMD across all skeletal sites: 12.4% at the lumbar spine (1.06 vs 1.21 g/cm²; P < .001), 8.5% at the femoral neck (0.86 vs 0.94 g/cm²; P < .001), and 14.8% at the total hip (0.86 vs 1.01 g/cm²; P < .001).
• Levels of both osteoblastic (P1NP) and osteoclastic (B-CTX) markers were elevated, with free triiodothyronine showing strong positive correlations with ALP (P = .005), B-CTX (P < .001), and P1NP (P = .004).
• Postsurgical analysis revealed significant reductions in levels of bone turnover markers: ALP level decreased from 91 to 71 U/L (P = .003) and B-CTX level from 0.75 to 0.22 ng/mL (P = .008).
• BMD was slightly but nonsignificantly increased at the lumbar spine and hip sites following surgery.

IN PRACTICE:

“Following complete tumor resection, bone turnover markers decreased significantly with concomitant stabilization of bone mineral density. These findings emphasize the importance of bone health assessment and management in TSHoma [TSH-secreting adenoma] patients alongside standard pituitary tumor care,” the authors of the study wrote.

SOURCE:

The study was led by Jie Liu, MD, Peking Union Medical College Hospital, Beijing, China. It was published online in Endocrine Practice.

LIMITATIONS:

Selection bias may exist because physicians preferentially order BMD tests for patients perceived to be at higher risk. The absence of primary hyperthyroidism BMD data for comparison prevented direct assessment of BMD differences between TSH-secreting adenomas and primary hyperthyroidism. Additionally, poor compliance with postoperative BMD follow-up assessments resulted in a significantly reduced sample size of only 13 patients with complete paired pre- and postoperative BMD data.

DISCLOSURES:

This research was supported by a grant from the National High Level Hospital Clinical Research Funding. The authors of the study reported having no relevant financial or nonfinancial competing interests to disclose.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.