Pineocytoma

A rare, slow-growing brain tumor originating from the pineal gland

Pineocytoma is a rare type of brain tumor that arises from the pineal gland, a small endocrine gland located near the center of the brain. Pineocytomas are generally considered to be slow-growing and are classified as World Health Organization (WHO) grade I tumors. They are distinct from pineoblastomas, which are more aggressive and classified as WHO grade IV.

Pathophysiology

The pineal gland is responsible for the production of melatonin, a hormone that regulates sleep-wake cycles. Pineocytomas originate from the pinealocytes, the primary cell type of the pineal gland. These tumors are typically well-circumscribed and composed of small, uniform cells with round nuclei and scant cytoplasm.

High magnification micrograph of a pineocytoma.

Clinical Presentation

Patients with pineocytoma may present with symptoms related to increased intracranial pressure due to obstruction of the cerebrospinal fluid pathways, leading to hydrocephalus. Common symptoms include headache, nausea, vomiting, and visual disturbances. In some cases, Parinaud's syndrome, characterized by vertical gaze palsy, may occur due to compression of the tectal plate.

Diagnosis

The diagnosis of pineocytoma is typically made through a combination of neuroimaging and histopathological examination. Magnetic resonance imaging (MRI) is the preferred imaging modality, often revealing a well-defined mass in the region of the pineal gland. Definitive diagnosis is confirmed by biopsy and microscopic examination, which shows the characteristic features of pineocytoma.

Treatment

The primary treatment for pineocytoma is surgical resection. Due to the tumor's location, surgery can be challenging, and a multidisciplinary approach is often required. Complete resection is associated with a favorable prognosis. In cases where complete resection is not possible, radiotherapy may be considered.

Prognosis

Pineocytomas generally have a good prognosis, especially when complete surgical resection is achieved. The risk of recurrence is low, and long-term survival rates are high. However, regular follow-up with imaging is recommended to monitor for any signs of recurrence.

Related pages

• Pineal gland
• Pineoblastoma
• Intracranial pressure
• Hydrocephalus