Variable hormonogenesis in Cushing's syndrome.

Four patients with Cushing's syndrome and variable cyclic hormonogenesis are reported and 40 other cases from the literature are reviewed. These cases were divided into four categories depending on regular or irregular cyclic adrenal hypersecretion and presence or absence of concomitant fluctuations in the clinical course. The manifestations of cyclic adrenal hypersecretion in these patients varied from daily to yearly intervals. Cyclic activity persisted for as long as 25 years, with cycle lengths varying from 12 hours to 85 days. Some patients demonstrated complex biochemical cyclic patterns. Clinical presentations varied from a single outstanding symptom, such as recurring oedema, to a complex clinical syndrome. The aetiology in these patients varied: 12 appeared to be pituitary dependent, 11 had corticotropin-producing tumours and another eight were described as showing 'adrenal hyperplasia'. A hypothalamic disorder was found in four, a benign adrenal adenoma in two, and an adrenal 'mass' and adrenocortical nodular dysplasia in single patients. Evaluation during the intercyclic phase may reveal normal pituitary function. Inconsistent responsiveness to administration of dexamethasone in different phases of cyclic activities may suggest the presence of cyclic Cushing's syndrome.