A Case Report Of Successful Postoperative Treatment With Octreotide For Thyroid-Stimulating Hormone/Growth Hormone-Producing Pituitary Adenoma

摘要

A 61-year-old man with high levels of alkaline phosphatase was admitted to our hospital presenting SITSH. He was diagnosed as TSH/GH-producing pituitary adenoma. After transsphenoidal adenectomy high serum values of GH, IGF-I, FT3, and FT4 and normal one of TSH still remained because of incomplete resection. In addition to oral administration of cabergoline, 20mg octreotide was administerd. Two months later, his serum TSH and GH levels were well controlled, and the successful response of the patient to octreotide can be attributed to 2 pathological factors, somatostatin-receptor-2-subtype and low Ki-67 SI. Introduction TSH-producing tumors are relatively rare, comprising 0.5–1% of pituitary tumors, and 15% of those secrete growth hormone (GH) 1. Although the primary treatment method for such tumors is resection, the administration of somatostatin analogs such as octreotide and dopaminergic drugs such as cabergoline can be effective in cases where tumors cannot be fully resected 2. Octreotide, in particular, is thought to be effective against tumors with the somatostatin-receptor (SSTR) 2-subtype that exhibit low proliferation potency (Ki-67 SI) 3. We herein report a case of a patient with thyroid-stimulating hormone (TSH)/GH-producing pituitary adenoma treated with transsphenoidal adenomectomy. Postoperative octreotide administration was successful, and both factors that influenced octreotide effectiveness were pathologically confirmed. Case Report The patient was a 61-year-old man with hypertension and type 2 diabetes showed high levels of serum alkaline phosphatase, and was diagnosed as a syndrome of inappropriate secretion of TSH (SITSH). He was referred to our hospital for further examination and treatment. He had no other past history or family history of metabolic or endcrinological disorder.On admission to our hospital, his physical condition was as follows: height, 170 cm; weight, 59.2 kg; body mass index, 20.5 kg/m2; blood pressure, 164/86 mmHg; heart rate, 76/min; and body temperature, 36.6°C. He showed macroglossia and protrusion of the lower jaw without signs of von Graefe nor eyeball protrusion. Diffuse enlargement of thyroid gland (Ⅱ / Sichijo’s classification) was apparent, but no finger tremor was observed. The patient presented macrosis of the hands and feet, but no edema was noted in the lower limbs.Blood cell counts and serum biochemical data showed normal study (Table 1). His free tiiodothyronine (FT3) and free thyroxine (FT4), as well as TSH levels increased, suggesting SITSH (Table 2). TSH receptor antibody (TRAb), anti-thyrogloblin and anti-thyroid peroxidase antibodies were negative. At the same time, both GH (23.11 ng/mL) and insulin-like growth factor (IGF)-I (627 ng/mL) were significantly high at his age. Chest radiograph revealed that a cardiothoracic ratio (CTR) of 42%. Electrocardiograms revealed normal sinus rhythm. Thyroid gland echography revealed diffuse swelling of both lobes and isolated small cysts, but internal blood flow was normal. Pituitary gland magnetic resonance imaging (MRI) showed an approximately 30-mm large tumor that bilaterally invaded the cavernous sinus (Figure 1). A thyrotropin releasing hormone (TRH) loading test revealed TSH unresponsiveness. There was no paradoxical GH elevation by TRH. 75-g oral glucose tolerance test (OGTT) showed that glucose load could not suppress GH secretion from the tumor (GH; 0-min 16.00 ng/mL, 120-min 8.54 ng/mL).