Clinical and Therapeutic Characteristics of Pituitary TSH-Secreting Adenoma in Adolescent-Onset Patients: Six Case Studies and Literature Review

BACKGROUND: Thyrotropin-secreting adenoma (TSH-oma) is a very rare kind of functional pituitary adenoma, especially that which occurs in adolescents. However, its potential clinical and therapeutic characteristics are still unknown. OBJECTIVES: The study was aimed to summarize the clinical and therapeutic characteristics of patients with adolescent-onset TSH-oma. METHODS: We retrospectively analyzed six (4.1%) adolescent-onset TSH-oma cases from 148 patients who were diagnosed with TSH-oma at our hospital between January 2012 and October 2020. A literature review was performed on the PubMed online database, and 14 adolescent-onset TSH-oma cases were retrieved. Then, the characteristics of clinical manifestations, treatment outcomes, and follow-ups were analyzed and compared to the adult TSH-oma patients. RESULTS: Altogether, 20 adolescent-onset cases were included in this study having mean onset age of 13.4 ± 3.3 years. Males were found to be slightly predominant (M: F = 1.5:1) in our study. The median baseline levels of TSH, FT3, and FT4 in adolescent-onset cases were found to be 6.30 [interquartile range (IQR) 9.82] µIU/ml, 9.18 (IQR 11.61) pg/ml, and 3.22 (IQR 1.90) ng/dl, respectively, which were all significantly higher than the adult patients of our hospital. Also, the adolescent-onset cases showed more large tumor ratio (36.8% vs. 9.3%, p = 0.007) compared to the adult patients. Compared to the patients of all ages in the literature, the biochemical remission rate of SSAs (57.1%) and remission rate of TSS (38.9%) were found to be considerably lower in adolescent-onset patients, while the recurrence rate (44.4%) was found to be considerably higher. CONCLUSIONS: Adolescent-onset TSH-oma patients showed higher TSH and thyroid hormone levels, more large tumors, and worse treatment outcomes than adult cases. Hence, early diagnosis, multidisciplinary therapy, and close follow-up should be highlighted to improve the prognosis.