TSH-induced hyperthyroidism caused by a pituitary tumor.

Area of Science:

• Endocrinology
• Neuroendocrinology
• Oncology

Background:

• A 45-year-old male with a 5-year history of poorly managed hyperthyroidism presented with headache and visual disturbances.
• He also experienced 2 years of erectile dysfunction and decreased libido, with physical findings of a small goiter, reduced testicular volume, and sparse pubic hair.

Observation:

• Diagnostic investigations included serum hormone levels (free T3, T4, prolactin, testosterone, gonadotropins, IGF-1, ACTH, cortisol), pituitary MRI, TSH-releasing hormone test, T3 suppression test, and measurement of pituitary glycoprotein hormone alpha-subunit and sex-hormone-binding protein.
• The patient was diagnosed with hyperthyroidism resulting from a mixed pituitary adenoma secreting both prolactin and TSH.

Findings:

• Trans-sphenoidal resection of the pituitary tumor was performed.
• Post-surgery, a T3 suppression test indicated persistent residual adenomatous cells, leading to recurrence of hyperthyroidism and hypogonadism after 5 years.
• Treatment with lanreotide resulted in complete resolution of disease signs and symptoms.

Implications:

• This case highlights the complexity of managing pituitary adenomas co-secreting multiple hormones.
• Recurrence of symptoms after initial treatment underscores the need for long-term monitoring and alternative therapeutic strategies.
• Lanreotide demonstrated efficacy in managing persistent or recurrent hyperthyroidism and hypogonadism due to pituitary adenoma.