ECE2015 Guided Posters Pituitary – Hypopituitarism (9 abstracts)
Background and objective: Atypical pituitary adenomas (APA), in 2004, were defined according to WHO classification, as those with Ki-67>3%, excessive p53 expression and increased mitotic activity and invasive behaviour. The real usefulness of this classification is still controversial, so we reviewed compared clinical and prognostic features in our typical and atypical pituitary adenomas.
Patients and methods: We retrospectively reviewed 343 consecutive pituitary adenomas (PAs). APAs occurred in 18.7% of cases. All patients were operated on in the Department of Neurosurgery at our institution and followed up at the Hypothalamic-Pituitary Disease Unit of the same institution. None patient had an adjuvant treatment pre-neurosurgery. Median follow-up time in our series was 75 months (range: 7345 months).
Results: More frequently APAs were diagnosed in younger patient. However we found a similar prevalence of APAs in male and female patients. A higher risk of being affect for an APA was identified in cases characterised by an ACTH- and PRL-immunohistochemical positivity. According to WHO classification, cavernous sinus invasion was associated with higher risk of being affected of an APA and consequently a higher risk of a partial PA neurosurgery resection. In our series we separately analysed recurrence and disease free survival time (DFST) in patients undergone radical neurosurgery (219 cases). In this group of radically resected PAs, we find a similar risk of recurrence-disease and a superimposable DFST between typical and atypical pituitary adenomas. Moreover, in this series we found that Ki-67 expression>1.5% was associated to a higher risk of recurrence and to a worse DFST, even after correction for age at diagnosis, gender, immunohystochemical classification, tumor size, invasiveness and Knosp classification (P=0.01; HR: 2.572; 95% CI: 1.2515.285). PAs with Ki-67>1.5% showed a worse DFST as compared to PAs with Ki-67<1.5% (HR: 2.166; 95% CI: 1.1544.064).
Conclusion: In this series, atypical and typical PAs didnt differ for recurrence and DFST. PAs with Ki-67≥1.5% showed a higher recurrence risk and a worse DFST as compared to PAs with Ki-67<1.5%. We suggest that a Ki-67≥1.5% may be useful as prognostic marker.