[Idiopathic hypophyseal hyperplasia: diagnosis by magnetic resonance]

Hypophyseal hyperplasia is an uncommon disorder in which the gland increase in size due to excessive proliferation of strings of normal cells, which usually secrete prolactin. Different aetiologies may cause this disorder of the hypophyseal gland. However, in a small number of cases the hyperplasia is not due to any of these aetiologies and is therefore known as idiopathic hypophyseal hyperplasia. There are few references in the literature to idiopathic hypophyseal hyperplasia with hyperprolactinaemia. Usually diagnosis is reached after treatment for a hypophyseal adenoma, since the clinical features are similar.

We present three cases seen in our department, in which hormone and endocrine studies were done to exclude known causes of hyperplasia, together with CT and MR scans. We analyzed the behaviour of hypophyseal hyperplasia by using imaging techniques, and the differential aspects with regard to hypophyseal adenomas. Firm diagnosis is only made on anatomopathological study of the hypophysis. However, we consider that sound knowledge of the characteristics of this condition may help to establish the correct diagnosis and thus avoid unnecessary surgery.

We review the information published in the literature on this subject, emphasizing the importance of differential diagnosis by means of imaging techniques.