The relationship between temporal muscle thickness and disease activity in Cushing's disease.

Objective: This study aimed to investigate the relationship between hypercortisolism and temporal muscle thickness (TMT) in Cushing's disease (CD).

Methods: A retrospective review of medical records was conducted for patients with CD who presented to our clinic between 2012 and 2022. Biochemical data and TMT measurements from sella imaging were evaluated during diagnosis and the first postoperative year.

Results: A total of 44 patients were included in the study, with an average age of 43.9 years, of which 38 were female. The mean TMT at the time of diagnosis was 19.07 ± 1.71 mm, with no significant difference between males and females (p = 0.097), and no correlation between the TMT and age at diagnosis (p = 0.497). There was an inverse relationship between TMT and serum cortisol levels, 24-h UFC, and midnight salivary cortisol at the time of diagnosis of CD (p < 0.05, for all). One year after surgery, TMT significantly increased in all patients compared to baseline (p < 0.001). Furthermore, patients who achieved postoperative remission had significantly higher TMT values compared to those who did not achieve remission (p = 0.043). Among the patients who achieved remission, those who achieved remission through surgery had significantly higher TMT compared to those who could not reach remission with surgery and patients who started medical treatment and achieved biochemical remission (p = 0.01). Patients with severe myopathy and sarcopenia had significantly lower TMT values than the others (p < 0.001).

Conclusion: Temporal muscle thickness was found to be associated with disease activity and disease control in Cushing's disease.