Intrasellar dermoid cysts are extremely unusual lesions, with only four cases reported to date, and have not been previously reported in association with sudden-onset symptoms. Here, we present the case of an intrasellar dermoid cyst with sudden-onset symptoms mimicking pituitary apoplexy in an elderly woman. A 69year-old woman presented with sudden onset of headache, dizziness, and decreased visual acuity. Magnetic resonance imaging of the sellar region showed an intrasellar lesion, which showed mixed hyper- and hypointense signal on T1-weighted and T2-weighted images and enhanced peripherally. Endocrine workup showed pituitary hormones within normal levels. According to these findings, the initial diagnosis of nonsecreting pituitary macroadenoma apoplexy was made. Intraoperatively, a large amount of whitish-yellow purulent material was found in the mass and the lesion was partially removed, owing to tight adhesion between remanent mass and surrounding neurovascular structures. Pathology showed a dermoid cyst with abundant neutrophil infiltrations.