A disorder caused by the increased secretion of growth hormone by an ADENOMA of the anterior PITUITARY GLAND. It results in excessive growth of both the skeleton and soft tissues (muscles etc). If it occurs in adolescence before the bones have stopped growing, the result is gigantism; if it occurs in adult life the skeletal overgrowth is confined to the hands, feet, cranial sinuses and jaw. Most of the features are due to overgrowth of the cartilage of the nose and ear and of the soft tissues which increase the thickness of the skin and lips. The thyroid gland and liver are also affected.
The local effects of the tumour commonly cause headache and, less frequently, impairment of vision from pressure on the nerves to the eye, particularly of the temporal (outwards) field. The tumour may damage the other pituitary cells, giving rise to gonadal, THYROID or adrenocortical insufficiency. Patients may also complain of excessive sweating, joint pains and lethargy. The diagnosis is confirmed by measuring the level of growth hormone in the serum and by an X-ray of the skull, which usually shows enlargement of the pituitary fossa, an indentation of the skull in which the PITUITARY GLAND sits.
The most effective treatment is surgery to remove the pituitary adenoma. This can usually be done via ENDOSCOPY through the nose and the SPHENOID sinus, but large adenomas may need a full CRANIOTOMY. Surgery cures about 80 per cent of patients with a microadenoma and 40 per cent of those with a large lesion; the rate of recurrence is 5–10 per cent. For recurrences and for patients unfit for surgery or who refuse it, drugs which inhibit growth hormone production are advised, including octreotide and lanreotride. DOPAMINE agonists such as bromocriptine are also used. Where these are not successful, X-ray therapy to the pituitary fossa may be offered.