Management of Cushing's disease: outcome in patients with microadenoma detected on pituitary magnetic resonance imaging

Abstract

Outcomes of therapy for Cushing's disease (CD) vary depending on different aspects of presentation and diagnostic studies. The authors designed this study to verify the remission rate and outcomes after transsphenoidal surgery (TSS) for patients with CD who had positive findings on MR imaging. Patients who had presented with CD at the University of Virginia for initial treatment between July 1992 and December 2005 were retrospectively reviewed. The patients included in the study were considered to be optimal surgical candidates, defined as an adult (>18 years of age) with classic clinical features of CD, laboratory studies confirming a central (pituitary/hypothalamic) adrenocorticotropic hormone-dependent source of disease, and an MR imaging study revealing a microadenoma in the sella turcica. A total of 167 patients fulfilled the criteria. Thirty were men (18%) and 137 were women (82%). The mean age was 42.3 years (range 18.2-77 years). All patients underwent TSS. Surgical remission was achieved in 148 patients (88.6%), which was correlated with the surgeon's intraoperative identification of an adenoma (p=0.03). Histopathological confirmation of an adrenocorticotropic hormone-secreting adenoma strongly correlated with remission (p=0.0001). Three patients (1.8%) had postoperative cerebrospinal fluid leaks, and 1 patient had meningitis. Transient diabetes insipidus was diagnosed and treated in 10 patients (6%), whereas permanent diabetes insipidus occurred in 8 patients (4.8%). Panhypopituitarism followed the surgery in 14 patients (8.3%), 13 of whom underwent total hypophysectomy (9 initially and 4 with early reoperations), and in 1 of 10 patients who underwent subtotal hypophysectomy. Nineteen patients (12.8%) who were initially in remission developed recurrent CD after an average of 50 months. The mean follow-up for the 167 patients was 39 months (range 6-157 months). Gamma Knife surgery was the most common modality of radiotherapy used to treat 31 patients (18.5%) who did not achieve remission or later presented with recurrent disease. Bilateral adrenalectomies were performed in 10 patients in the series (6%), 2 of whom developed Nelson's syndrome. The overall posttreatment remission rate was 95.8%. Even in patients with ideal diagnostic criteria of CD, there remain a significant number of cases in which TSS alone is not adequate to assure long-lasting remission. A multidisciplinary approach is essential to the achievement of satisfactory overall remission rates.