Clinicopathological variations in Cushing's syndrome

In the majority of cases, Gushing's disease is the result of a small basoph ilic corticotroph microadenoma with an average size of less than 5 mm. Tran ssphenoidal microsurgery can cure patients with Gushing's disease; however, selective removal of the lesion requires precise preoperative localization . In this article, we present the pathological findings and clinical outcom es of four patients who underwent inferior petrosal sinus sampling (IPSS) f or ACTH, pituitary imaging and subsequent transsphenoidal surgery for the d iagnosis and treatment of Gushing's disease. All patients fulfilled accepte d biochemical criteria for the diagnosis of ACTH-dependent Gushing's syndro me. Histological examination revealed a basophilic corticotroph adenoma in two patients. In one other patient, only Crooke's hyalinization was found; however, the patient achieved a complete clinical and biochemical remission following a hemihypophysectomy based on IPSS findings. Thus, a microadenom a was assumed or proven in three patients, of whom two were cured by surger y alone. In the third patient, cortisol excess persisted following transsph enoidal surgery because of a coexistent functioning adrenal adenoma. The fo urth patient developed recurrent nodular corticotroph hyperplasia following a 17-yr remission. The second transsphenoidal procedure failed to ameliora te cortisol excess, necessitating a subsequent bilateral adrenalectomy. IPS S accurately localized the site of the lesion in all four cases. Although m agnetic resonance imaging (MRI) identified a distinct lesion in three cases , two of these represented false positives (a cyst in one case and a prolac tinoma in the other), whereas in only one did MRI correctly match the site of the lesion. In each case, conflicting test results and/or difficult mana gement decisions posed a challenge. Thus, successful resolution of disease requires a multidisciplinary approach to validate clinical, biochemical, an d radiographic data based on morphologic findings.