Cavernous sinus invasion might be a risk factor for apoplexy.

The clinical features of pituitary hemorrhage vary from asymptomatic to catastrophic. We aimed to evaluate the frequency, symptoms, outcome and risk factors of clinical and subclinical pituitary apoplexy (PA) patients. In a retrospective analysis, charts of 547 pituitary adenoma patients from 2000 to December 2011 were reviewed. The patients were classified as clinical or subclinical PA. We compared the results with a control group without PA. Anterior pituitary hormones for endocrine dysfunction, histology, Ki-67 labeling index (LI), and p53 positivity of the tumor and pituitary imaging by magnetic resonance imaging were evaluated. Thirty-two patients (5.8%) were diagnosed as clinical and 81 patients (14.8%) as subclinical PA. Among PA patients, 85 patients (75.2%) had a macroadenoma, 8 patients (7.1%) had a microadenoma. The most frequent symptoms at presentation in PA patients were visual loss and headache. The patients with macroadenoma had a significantly increased risk for PA (p < 0.05). Hormone inactive tumors were significantly associated with the development of clinical PA (p = 0.05). Dopamine agonist use was significantly higher in subclinical PA patients (p = 0.001). Sex, Ki-67 LI, p53 positivity, diabetes mellitus, hypertension, somatostatin analogue and anticoagulant use did not predispose to PA whereas cavernous sinus invasion predisposed patients to PA (p < 0.01). The incidence of subclinical PA is higher than that of clinical PA. The development of PA is associated with macroadenomas. Clinically non-functioning tumors predispose to clinical PA. Cavernous sinus invasion of the tumor may be a sign of increased risk of bleeding.