THYROIDITIS DEVELOPING POST INITIATION OF OCTREOTIDE IN A CASE OF TSH SECRETING TUMOR

Area of Science:

• Endocrinology
• Oncology
• Immunology

Background:

• Thyroiditis post pituitary surgery for TSH secreting tumors is rare.
• A patient with presumed hypothyroidism was found to have an unsuppressed TSH despite thyroxine treatment.
• Diagnostic workup revealed a TSH secreting pituitary tumor with cavernous sinus invasion.

Purpose of the Study:

• To report a rare case of TSH secreting pituitary tumor treated with octreotide.
• To investigate the development of thyroiditis following octreotide therapy.
• To explore the potential immunomodulatory mechanisms involved.

Main Methods:

• Diagnosis of TSH secreting pituitary tumor based on suppressed TSH, cyclic T3 secretion, and pituitary MRI.
• Treatment initiated with octreotide.
• Thyroid function tests (TFTs), tumor size, goiter size, Anti-TPO antibodies, and Fine Needle Aspiration Cytology (FNAC) of the thyroid were monitored.

Main Results:

• Octreotide normalized TFTs within 4 days and reduced tumor size by 30% in 2 months.
• Goiter size significantly reduced with octreotide therapy.
• Anti-TPO antibodies became positive, and FNAC confirmed thyroiditis within a month of octreotide initiation.

Conclusions:

• Octreotide therapy is effective for TSH secreting pituitary tumors, normalizing thyroid function and reducing tumor size.
• The development of thyroiditis post-octreotide therapy is a rare but observed phenomenon.
• The immunomodulatory effects of TSH and somatostatin may contribute to the induction of thyroiditis.