Isolated acquired ACTH deficiency and primary hypothyroidism: a short series and review.

Idiopathic isolated ACTH deficiency, congenital or acquired, is rare. It may be found in association with primary hypothyroidism. Here we describe four cases of acquired idiopathic isolated ACTH deficiency illustrating its importance and variable presentation. All cases had a structurally normal pituitary gland and persistently normal residual pituitary function. Three cases had co-existing primary hypothyroidism. We discuss the protean presentation of this rare but important condition, its treatment, associations, and possible aetiologies.