Pituitary adenomas are uncommon in childhood (Zimmerman, 1969). The majority of pituitary adenomas are benign hormonally active tumours arising from the 5 hormonal secreting cell types of the adenohypophysis (Asa and Kovacs, 1983). With the availability of modern immunohistochemical techniques it is apparent that only 25% of pituitary adenomas are non-functioning.
In paediatric practice the important hormonally active adenomas are GH (gigantism), prolactin and ACTH (Cushing's disease). Both functional and non-functional pituitary tumours may be associated with hypopituitarism resulting from compression of the normal pituitary tissue or from tumour interfering with transport and synthesis of hypothalamic releasing hormones. This may lead to impaired growth, hypothyroidism, hypoadrenalism and failure of normal pubertal development.
The excessive secretion of GH before fusion of the epiphyses leads to gigantism. After fusion it produces the typical features of acromegaly. In nearly all cases, gigantism results from a pituitary tumour. Some tumours are mixed and