Endocrine Abstracts

Background: Anecdotal reports have suggested that silent ACTH tumours behave in an aggressive fashion, however, clear comparative data are lacking.

Methods: 28 patients (16 men, mean age 51.3years [range 30-80years]) who underwent trans-sphenoidal surgery in Oxford between 1975 and 2001 for clinically non-functioning adenomas where the subsequent immunostaining was positive for ACTH were identified from the patient database. The mean follow-up period was 89.2months (range 6-323months).

Results: The recurrence rate in the ACTH positive tumours was 32% at a mean of 5.8years (range 1-16years) which is identical to the previously published recurrence rate in all non-irradiated non-functioning tumours managed in our department (Turner et al,1999). In two of our 28 patients this recurrence occurred despite prophylactic irradiation while seven of the patients have subsequently received conventional radiotherapy post their recurrence. One patient has suffered two recurrences (three operations and two courses of radiotherapy) and one patient has had three recurrences (four operations, two courses of radiotherapy & gamma knife therapy). Visual field defects were documented in 79% of the 28 patients at presentation (69% in the non-functioning population as a whole) and the pre-operative imaging (13 CT, 14 MRI & one air encephalogram) revealed 68% Grade 2 (modified Hardy classification) and 32% Grade 3 adenomas. None of the patients had clinical evidence of Cushing's syndrome.

Conclusion: This is the first time that studying a significant series of ACTH positive tumours has demonstrated that they do not recur more often than ACTH negative / gonadotrophin staining tumours. However, when these tunours do regrow they show a more aggressive course.