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Neoplasms may be one of the systemic complications to which we attribute high mortality in acromegaly. The present study was designed to investigate the incidence of malignant tumors in patients with acromegaly in the Japanese population. In this report, 44 patients (25 men and 19 women) with biochemically proven acromegaly were studied retrospectively and had a total 670 patient years of the duration of acromegaly. We investigated the incidence of malignant tumors. There were 5 patients with malignant tumors (5 in men) in this study (11%). Male patients with acromegaly had nearly a 3.5 times higher ratio of malignancy than expected and this increased cancer incidence was considered significant (P=0.01). There was no significant increase in cancer incidence of either the total patient population or female patients. The malignant tumors were two thyroid cancers and one colon, one gastric and one bladder cancer. It is of note that the colon cancer of one patient was diagnosed 2 years after transsphenoidal surgery even though the levels of serum GH and insulin-like growth factor (IGF-1) were reduced to normal after operation. This preliminary study has suggested that male patients with acromegaly might have a high risk of malignancy and that careful screening for tumors is needed both before and after surgical and medical treatment, even in patients with normalized serum GH and IGF-1 levels.

This is a case report of an 18-year-old man with central diabetes incipidus (DI). An MRI done three months after the onset of the DI did not disclose a responsible lesion. Four months later, a second MRI showed the location of the tumor origin at the upper pituitary stalk and median eminence. Eight months later, the tumor occupied the hypothalamic area. The tumor became large and contrast-making enough to be visible on MRI between 3 and 4 months after the onst of DI. Besides the suprasellar tumor, another mass was noted in the pineal region. The growth pattern of the latter mass corresponded well to that of the former. Although the MRI is a sensitive diagnostic tool for the detection of intracranial tumors, no adequate rationale has been given as to how the MRI might be repeated for children and adolescents who have been diagnosed as having the central DI, when their initial MRIs may have been normal. In our patient, the superconductive thin slice MRI revealed the suprasellar germinoma 4 months after the onset. The suprasellar and pineal tumors in this report originated and developed simultaneously. This may indicate a multi-center origin of the tumor. Another possibility is a very early dissemination from the onset of the tumor development.

We report a rare case of a 40-year-old woman with Cushing's syndrome and Acromegaly. At the age of 28 she was diagnosed with Cushing's syndrome due to a left adrenal tumor concomitant with a GH-producing pituitary tumor. Before adrenal surgery her basal GH levels were extremely high and CT scanning revealed a high-density mass in the sella turcica. A 28 g left adrenocortical adenoma was removed by adrenalectomy. During the four months after the adrenalectomy, basal GH levels dramatically decreased and the high-density mass detected by CT scanning had disappeared but the basal GH levels and IGF-1 had not been normalized. She gradually became acromegalic in the twelve years after the adrenalectomy. At the age of 40 CT scanning showed reappearance of the pituitary tumor. In order to examine the glucocorticoid dependency on GH secretion, we compared the GH secretion in a series of endocrinological tests before and after oral 8 mg dexamethasone administration for 7 days. There was no difference between before and after dexamethasone administration in the GH secreting pattern, but basal GH levels were apparently increased after dexamethasone treatment. Transsphenoidal surgery was done and pathological examination showed a GH-producing pituitary adenoma. In vitro, dexamethasone increased GH secretion from the cultured GH-producing adenoma cells in a dose-dependent manner. In this case, both GH secretion and pituitary tumor growth seemed to be dependent on glucocorticoid.

We saw a remarkable effect of octreotide, the long-acting somatostatin analogue, in reducing the number of ventricular premature complexes (VPCs) in a 59-year-old woman with acromegaly. Her basal GH and IGF-1 levels were up to 22.9 ng/ml and 934.9 ng/ml respectively. MRI revealed a 14 x 12 x 10 mm mass lesion in the pituitary gland. She had hypertension and echocardiography showed an increase in left ventricular wall thickness. Electric cardiography showed the presence of frequent VPCs and 24-h Holter monitoring revealed 24,277 beats of multifocal VPCs/24 h. She was treated with 300 microg/day of octreotide for four weeks before transsphenoidal surgery. After octreotide treatment, GH and IGF-1 were suppressed to 1.8 ng/ml and 145.3 ng/ml respectively, and the tumor size was remarkably reduced. Furthermore, the number of VPCs was also dramatically reduced to 2062 VPCs/24-h (8.5% of pretreatment) with 24-h Holter monitoring. This case shows that VPCs of acromegalic patients can be controlled by suppressing GH and IGF-1 with octreotide, and this agent is useful for reducing both tumor size and frequency of VPCs prior to surgery.