[A case of non-neoplastic pineal cyst presenting Parinaud's syndrome].

A case of non-neoplastic pineal cyst with Parinaud's syndrome is presented. A 54-year-old woman was admitted to the department of neurosurgery. Fukui Medical School on October, 1985, complaining of the paralysis of upward gaze. A computed tomography (CT) demonstrated a low density mass in the pineal region and the mass was not enhanced after the injection of contrast agent. Metrizamide CT cisternogram delineated the mass clearly. Bilateral carotid and vertebral angiograms showed no significant findings. On November 5, an operation was performed by means of an occipital transtentorial approach. A cyst filled with clear yellowish fluid was found in the pineal region. The cyst was evacuated and its wall was subtotally resected. The histological examination revealed the cystic cavity lined by fibrous astrocytes which were surrounded by normal pineal tissue. Therefore the cyst was diagnosed as a non-neoplastic pineal cyst. The postoperative course was uneventful. The paralysis of upward gaze was gradually improved. On December 27, the patient was discharged in excellent condition. Non-neoplastic small cysts which do not cause an enlargement of the pineal body are common incidental findings at autopsy, whereas large cysts which cause symptoms due to compression of the corpora quadrigemina and the production of internal hydrocephalus are rare. In this paper, non-neoplastic pineal cyst is discussed.