High serum levels of somatomedin-C and diabetes mellitus caused by obstructive hydrocephalus: case report.

Abstract

This case demonstrates a relationship between hydrocephalus with a huge diverticulum of the third ventricle and high serum levels of somatomedin-C. Somatomedin-C levels become high when the secretion of growth hormone from the adenohypophysis increases, and previous reports state that hydrocephalus decreases the secretion of growth hormone. The patient suffered from diabetes mellitus and obesity, and serum somatomedin-C levels were high. A pituitary adenoma or ectopic growth hormone-producing tumor was suspected. Magnetic resonance imaging did not reveal either of these abnormalities but indicated hydrocephalus with a diverticulum of the third ventricle. After ventriculoperitoneal shunt placement, the blood glucose and serum somatomedin-C levels of the patient decreased toward normal. Six months later, the shunt tube became obstructed and serum somatomedin levels increased. The levels decreased again after shunt revision. To our knowledge, this is the first published report of obstructive hydrocephalus with a diverticulum of the third ventricle compressing the hypothalamus and increasing the serum levels of somatomedin-C.