Delay in diagnosis is common in TSH-Secreting Pituitary Adenomas - Clinical and Endocrinological Profiles from a Retrospective Cohort Study

Introduction: TSH-secreting pituitary adenomas (TSHom) are rare causes of hyperthyroidism, often leading to diagnostic and therapeutic challenges. This study aims to characterize the clinical, biochemical, radiological, and histopathological features of TSHomas, evaluate treatment outcomes, and assess factors influencing disease remission and recurrence. Materials and Methods: A retrospective cohort study was conducted at a tertiary endocrine referral centre, including 12 patients diagnosed with TSHomas between January 2003 and February 2025. Clinical presentation, laboratory findings, imaging characteristics, histopathology, treatment approaches, and long-term outcomes were analysed. Diagnostic criteria included inappropriately normal or elevated TSH levels despite elevated free thyroid hormones, confirmed by pituitary imaging. Treatment modalities included transsphenoidal surgery (TSS), transcranial surgery (TNS), somatostatin analogues (SSAs), and radiotherapy. Remission was defined biochemically and clinically as the normalization of thyroid function and symptom resolution without ongoing therapy. Results: The cohort consisted of 9 males (75%) and 3 females (25%), with a mean age at symptom onset of 45.8 ± 17.5 years and a median diagnostic delay of 24 months. Common presenting symptoms included palpitations (50%), sweating (41.7%), and weight fluctuations (33.3%), while 25% exhibited symptoms related to tumour mass effects. MRI confirmed pituitary adenomas in all patients, with Knosp grade 3–4 tumours in 41.7%. Surgical resection was performed in 83.3%, with 50% achieving complete biochemical remission. Persistent or recurrent disease was observed in 33.3%, requiring additional therapies, including SSAs and radiotherapy. At a median follow-up of 7.8 years, 66.7% remained in remission. Genetic testing identified MEN1 mutations in 16.7% and a THβ mutation in 8.3% of patients. Discussion & Conclusion: TSHomas present with heterogeneous clinical and biochemical profiles, often leading to diagnostic delays. While surgery remains the primary treatment, multimodal approaches, including SSAs and radiotherapy, are necessary in cases of persistent or recurrent disease. Long-term follow-up is essential due to the risk of recurrence. Further research is needed to optimize treatment strategies and improve long-term outcomes in this rare condition.