Thyrotropin-producing pituitary adenoma simultaneously existing with Graves' disease: a case report

Abstract

Background: Thyrotropin-producing pituitary tumor is relatively rare. In particular, concurrent cases associated with Graves' disease are extremely rare and only nine cases have been reported so far. We describe a case of a thyrotropin-producing pituitary adenoma concomitant with Graves' disease, which was successfully treated.

Case presentation: A 40-year-old Japanese woman presented with mild signs of hyperthyroidism. She had positive anti-thyroid-stimulating hormone receptor antibody, anti-thyroglobulin antibody, and anti-thyroid peroxidase antibody. Her levels of serum thyroid-stimulating hormone, which ranged from low to normal in the presence of high levels of serum free thyroid hormones, were considered to be close to a state of syndrome of inappropriate secretion of thyroid-stimulating hormone. Magnetic resonance imaging showed a macropituitary tumor. The coexistence of thyrotropin-producing pituitary adenoma and Graves' disease was suspected. Initial therapy included anti-thyroid medication, which was immediately discontinued due to worsening symptoms. Subsequently, surgical therapy for the pituitary tumor was conducted, and her levels of free thyroid hormones, including the thyroid-stimulating hormone, became normal. On postoperative examination, her anti-thyroid-stimulating hormone receptor antibody levels decreased, and the anti-thyroglobulin antibody became negative. The coexistence of thyrotropin-producing pituitary adenoma and Graves' disease is rarely reported. The diagnosis of this condition is complicated, and the appropriate treatment strategy has not been clearly established.

Conclusions: This case suggests that physicians should consider the coexistence of thyrotropin-producing pituitary adenoma with Graves' disease in cases in which thyroid-stimulating hormone values range from low to normal in the presence of thyrotoxicosis, and the surgical treatment of thyrotropin-producing pituitary adenoma could be the first-line therapy in patients with both thyrotropin-producing pituitary adenoma and Graves' disease.

Keywords: Endoscopy; Graves’ disease; Neurosurgery; Pituitary neoplasms; TSH-producing tumor; TSHoma; Thyrotropin.

Fig. 1

Imaging study. a T1-gadolinium magnetic resonance imaging on admission showing a less enhanced area in the sella turcica, which seemed to be a macroadenoma (10×13 mm). b The tumor slightly invaded the right lateral cavernous sinus

Fig. 2

Levels of the anti-thyroid-stimulating hormone receptor antibody, thyroid-stimulating hormone, and free thyroxine. The free thyroxine level was above 1.5 ng/dL preoperatively. Total resection of the pituitary adenoma by endoscopic trans-sphenoidal neurosurgery was performed in January 2011. The free thyroxine level decreased within normal range. Subsequently, the euthyroid status was maintained. In the meantime, the thyroid-stimulating hormone values ranged from 0.1 to 0.5 μIU/mL preoperatively. The thyroid-stimulating hormone value of a typical patient with Basedow’s disease is less than 0.1 μIU/mL. In the case of syndrome of inappropriate secretion of thyroid-stimulating hormone, the thyroid-stimulating hormone value is more than 0.5 μIU/mL. The present case did not fit either of these two diseases. On postoperative examination, the thyroid-stimulating hormone value decreased below the detection threshold. Gradually, the thyroid-stimulating hormone values became normal. Anti-thyroid-stimulating hormone receptor antibody was continuously above the upper limit of normal range. FT4 free thyroxine, TRAb anti-thyroid-stimulating hormone receptor antibody, TSH thyroid-stimulating hormone

Fig. 3

Pathological diagnosis of pituitary adenoma was determined (a). Immunostainning showed the following: thyroid-stimulating horomone, strongly positive (b); follicle stimulating hormone, weakly positive; luteinizing hormone, negative; growth hormone, focally positive: prolactin, focally positive; and adenocotrophic hormone, negative