The exact incidence of pituitary apoplexy is difficult to estimate as many cases remain undiagnosed 1).
Some series indicate that the incidence of apoplexy in pituitary neuroendocrine tumors is between 1% and 26% on the basis of clinical signs coupled with surgical or histopathological evidence 2) 3).
Mohr and Hardy noted typical symptomatic pituitary apoplexy to occur in only 0.6% of patients with significant hemorrhagic and necrotic changes in 9.5% of surgical specimens.
In Wilson’s series, 3% of his patients with macroadenomas had an episode of pituitary apoplexy. In another series of 560 pituitary tumors, a high incidence of 17% was found (major attack in 7%, minor in 2%, asymptomatic in 8%) 4). It is common for apoplexy to be the initial presentation of a pituitary tumor 5).
The very low incidence of this complication hinders formulation of widespread guidelines on diagnostic and therapeutic management 6).
Frequency of intratumoral hemorrhage increases to 26% if using only MRI criteria without clinical evidence of apoplexy. However, hemorrhagic pituitary apoplexy may be fatal. Kurisu et al reported a 68-year-old man who developed pituitary apoplexy resulting in massive intracerebral hemorrhage and death 1 month later 7)
The male-to-female predominance is 2:1.
The age range is 37-57 years.
Male sex, non-functioning tumor, and macroadenoma are associated with an increased risk 8).