[A case of growth hormone-producing adenoma presenting as a non-functioning tumor at recurrence]

The authors report a case of recurrent pituitary adenoma, which changed its endocrinological function from GH producing to non-functioning. A 37-year-old woman was admitted to our hospital complaining of headaches, amenorrhea and acromegalic features. Skull X-rays showed marked ballooning of the sella turcica and mild thickening of the calvarium. X-rays of the hands and feet revealed moderate acromegalic changes. On pneumoventriculography, the tumor elevated the floor of the third ventricle. The serum GH level was 29.3 ng/ml, which did not respond to insulin induced hypoglycemia. Radical removal of the tumor was performed through a right frontal craniotomy. Histologically, it was diagnosed as a pituitary eosinophilic adenoma. Immunostains revealed the presence of many GH positive cells in the adenoma. Since the post-operative GH levels were still high (12-16 ng/ml), irradiation to the sellar region was carried out. The serum GH concentration gradually decreased to the normal level in one year after the irradiation. At that time no sellar tumor could be found on CT scans. The patient had been well for six years until she noticed hearing impairment of her right ear. She was re-admitted about seven years after the first admission because of cerebellar ataxia and hearing loss. CT scans revealed a recurrent tumor extending from the sellar region to the right cerebello-pontine angle. Serum GH levels on admission were within normal range (3-4 ng/ml). The tumor was partially removed by suboccipital craniectomy. Pathologically, the tumor was reported as a pituitary chromophobe adenoma. With immunostains, no GH positive cells could be found in the adenoma.(ABSTRACT TRUNCATED AT 250 WORDS)