Cortical hyperplasia of the adrenal gland in the dog.

A survey of the adrenal glands of 151 dogs revealed 33 cases of nodular cortical hyperplasia and six cases of diffuse cortical hyperplasia. The gross, microscopic and ultrastructural changes seen in these two forms of the condition are compared. Detailed measurements indicate that a morphometric study is of some value in establishing a post mortem diagnosis of hyperadrenocorticalism. Cell counts show that, despite differences revealed by histological examination, cellular hypertrophy may be in important feature in both nodular and diffuse 'hyperplasia'. Electron micrography suggests that the ultrastructural changes in nodular hyperplasia are of a degenerative nature while in diffuse hyperplasia the increased quantity of endoplasmic reticulum present and the appearance of the other organelles indicate hyperactivity. This correlates well with the clinical evidence of hyperadrenocorticalism seen in the latter condition.