Successful management of octreotide-insensitive thyrotropin-secreting pituitary adenoma with bromocriptine and surgery: A case report and literature review

Abstract

Rationale: Case reports concerning the value of dopamine agonists in the treatment of patients with thyrotropin-secreting pituitary adenoma (TSHoma) are limited. Herein, we present a rare case of octreotide-insensitive TSHoma responding to bromocriptine therapy.

Patient concerns: A 45-year-old Chinese man was admitted to Peking Union Medical College Hospital with marked clinical manifestations of hyperthyroidism.

Diagnoses: Thyroid function tests demonstrated elevated concentrations of free thyroid hormones in the presence of normal thyrotropin. Magnetic resonance imaging findings showed a pituitary microadenoma on the right side of the sellar region. Based on characteristic endocrine results and neuroimaging findings, the patient was diagnosed with TSHoma.

Interventions: Most patients with TSHomas are significantly responsive to somatostatin analog treatment. However, our patient was orally administered with bromocriptine to normalize thyroid function as assessed by suppression tests conducted prior to surgery. A transsphenoidal surgery was performed by an experienced neurosurgeon for tumor removal.

Outcomes: The pituitary lesion was totally resected. Following the operation, the results of thyroid function tests were immediately within reference limits. During the follow-up, there was no residual or recurrent tumor.

Lessons: Attention should be paid to the role of dopamine agonists such as bromocriptine and cabergoline as adjuvant therapy for TSHomas that are insensitive to traditional medical treatment by somatostatin analogs.

Figure 1

Preoperative MRI characteristics of the pituitary lesion: (A) coronal T1WI, (B) coronal T2WI, (C) coronal-enhanced T1WI, (D) sagittal-enhanced T1WI). MRI = magnetic resonance imaging, T1WI = T1-weighted image, T2WI = T2-weighted image.

Figure 2

Histopathological and immunohistochemical characteristics of thyrotropin-secreting pituitary adenoma: (A) hematoxylin and eosin stain × 100, (B) immunohistochemical stain for TSH ×100, (C) immunohistochemical stain for GH ×100, (D) immunohistochemical stain for PRL × 100. GH = growth hormone, PRL = prolactin, TSH = thyroid stimulating hormone.

Figure 3

Postoperative MRI characteristics of the pituitary lesion: (A) coronal-enhanced T1WI, (B) sagittal-enhanced T1WI. MRI = magnetic resonance imaging, T1WI = T1-weighted image.

Figure 4

Results of dynamic thyroid function monitoring with medical interventions (gray arrow: (A) start of bromocriptine, (B) start of octreotide and discontinuation of bromocriptine, (C) reuse of bromocriptine and discontinuation of octreotide, (D) pituitary surgery. Dotted line red: upper limit of the normal range, blue: lower limit of the normal range). TSH = thyroid-stimulating hormone, FT3 = free triiodothyronine, FT4 = free thyroxine.