Clinicopathological Features and Long Term Outcome Following Transsphenoidal Resection
Gordon Tang (Barstow, CA), Ming-Ming Ning, Marielle H. Nyugen, Brooke Swearingen, Nicholas T. Zervas (Boston, MA)
Discussant: Kalmon Post
Endocrine-inactive adenomas (EIA) account for 30% of pituitary tumors but are infrequently studied. We aim to characterize their clinical presentation, identify endocrinological and radiographic features, study pathological characteristics and determine long-term outcome. We have therefore retrospectively reviewed the cases on 357 patients who underwent resections of EIA from 1978 to 1996 with an average follow up of 8.4 years.
The group ranged in age from 16 to 82 years with a mean age of 52 6 years. Symptoms of mass effect, such as, visual field deficits (70%) headaches (48%), and ophthalmoplegia (7%), prompted diagnosis in most cases. Seven percent presented with apoplexy. Symptoms consistent with hypopituitarism were reported by a third of patients. Endocrine workup disclosed pituitary insufficiency in half of the patients, with deficits of ACTH (35%) and gonadotropins (33%) being the most frequent. Seven patients exhibited alphasubunit hypersecretion. Nearly all tumors were macroadenomas (93%), with a median size of 2.3 cm Immunostaining revealed that truly null tumors were less common than previously supposed (23.4%) with immunoreactivity for FSH (47%), LH (43%) and alpha-subunit (50.6%) higher than expected. Immunosectivity to other hormones suggests that EIA include a significant subpopulation of clinically silent endocrine tumors (ACTH 15%, TSH 16%, GH 7.9%; prolactin 12.8%) Although total resection was reported in 80% of cases, only 29% were free of tumor on follow-up imaging. Only 16% developed symptomatic recurrences despite the high incidence of residual tumor. Patients undergoing postoperative radiotherapy (RR=2.8, p<0.01) and those receiving complete resections (RR =5.5, p<0.01) were less likely to develop recurrences. Surgery improved headaches (92%) and visual field deficits (90%) in most patients. Thyroid insufficiency (35%) appeared to increase following surgery while steroid dependency (28%) decreased. Surgery infrequently reversed hypogonadism.
Based on these data we conclude that: 1) postoperative radiotherapy likely reduces the recurrence rate; 2) surgeon impression of resection underestimates residual tumor; 3) a complete resection lowers the recurrent risk; 4) surgery alleviates symptoms of mass effect but is less successful for treating hypopituitarism; and 5) most EIA are immunoreactive to LH, FSH, or alpha-subunit with a significant portion being clinically silent endocrine tumors.