Histopathology of Acromegaly Associated Pituitary Tumours (2)	

The secretion from pituitary adenomas is usually of GH alone, but the tumour may also be of mixed cell types and thirty per cent of acromegalic patients are also hyperprolactinaemic. Very occasionally GH and prolactin may originate from the same cell. GH cell adenomas occur in both sparsely and densely granulated forms. The latter look very similar to normal somatotrophs and the cells stain with acid dyes, representing the eosinophil adenoma in the conventional classification. By contrast, the sparsely granulated somatotroph adenoma represents the chromophobe adenoma. Clinically, the sparsely granulated somatotroph adenomas tend to be more aggressive, the cells show less differentiation and the tumour is more invasive.