Failure of total hypophysectomy to remove intrasellar microadenoma in cushing's disease

The pathological findings are described of a female patient with persistent Cushing's disease after two unsuccessful transsphenoidal operations: a left transsphenoidal hemihypophysectomy followed by a total hypophysectomy 1 month later. The patient was finally cured by bilateral adrenalectomy but suddenly died of heart failure 4 months later. Postmortem examination did not show invasive ACTH-secreting tissue in the pituitary region or an ectopic ACTH-secreting tumor, as initially presumed. Instead, a very small corticotroph adenoma was located immediately under the diaphragm sellae at the left side. The reasons for surgical failure in Cushing's disease are discussed. As in our patient, a missed small intrasellar adenoma must not be excluded when "total" hypophysectomy fails to cure Cushing's disease.