Pineal gland cyst

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

A pineal gland cyst is a cyst in the pineal gland, a small endocrine gland in the brain.. Statisically, these fluid-filled bodies appear on 1-4% of magnetic resonance imaging (MRI) brain scans. They are more frequent at death, seen in 21-41% of autopsies, though researchers are not sure why. They are in most cases asymptomatic, and it is rare for a pineal cyst to cause symptoms. If they do, these would most likely be headache, visual disturbances, or hydrocephalus, which can be extremely dangerous if left untreated. Pineal cysts are not cancer and most of the time they do not enlarge over 2 centimeters.

Asymptomatic cysts require no treatment. Some doctors choose to monitor patients with CT scans or MRI to look for cyst growth, but most doctors do not.

Differentiating Pineal gland cyst from Other Diseases

Pineal cysts are most often mistaken for and may be indistinguishable from a benign pineocytoma. Pineocytomas are more likely to have solid components.
Other cysts in the quadrigeminal cistern that mimic pineal cysts include arachnoid cysts and, rarely, epidermoids.

Diagnosis

Attenuation or signal intensity varies with cyst content.
One-fourth have rim or nodular calcium in the cyst wall on nonenhanced CT scans.
Rim or nodular enhancement is also common.
On T1-weighted MR images, 55%–60% are slightly hyperintense to CSF. Most do not appear hypointense on FLAIR images, and 60% enhance with use of contrast material.

Treatment


Management Options of Penial Gland tumors
CSF diversion	The optimal surgical strategy to treat acute hydrocephalus in patients with pineal tumors is uncertain. CSF diversion (ventriculoperitoneal [VP] shunt or third ventriculostomy may be necessary in symptomatic patients, although debulking surgery may obviate the need for this procedure When CSF diversion is necessary, endoscopic third ventriculostomy can be carried out at the same time as the biopsy and is preferred over VP shunts, which can be complicated by infection, shunt malfunction, subdural hematoma, and rarely, tumor seeding
Surgical resection	Some series report long-term survival with surgery alone, even in patients with pineoblastomas. Indeed, for pineoblastomas, gross total surgical resection appears to correlate with improved survival. Patients with symptomatic recurrent pineocytomas should also be considered for surgical resection of the lesion
Radiation	Postoperative adjuvant RT is frequently (but not universally) recommended, and local control is dose-dependent. The incidence of leptomeningeal recurrence was significantly lower among patients receiving CSI compared with those who did not. The five-year survival rates were 86 and 49 percent for pineocytomas and non-pineocytoma PPTs, respectively. Adjuvant RT is not universally recommended after gross total resection of a pineocytoma
Stereotactic radiosurgery	Stereotactic radiosurgery (SRS) is emerging as a useful treatment alternative for pineocytomas, although experience is limited. The precise radiation fields that are defined by MRI or CT-computerized treatment planning minimize damage to the surrounding brain, and the risks of general anesthesia and craniotomy are avoided. SRS is increasingly being used to treat pineal region tumors, either as an additional therapy after conventional treatments or as a primary treatment. Due to the low rate of side effects, IRS may develop into an attractive alternative to microsurgery in de novo diagnosed pineocytomas. In malignant PPTs, IRS may be routinely applied in a multimodality treatment schedule supplementary to conventional irradiation.
Chemotherapy as part of multimodality therapy	The similarity of pineoblastomas to medulloblastomas in terms of their clinical behavior and tendency for leptomeningeal seeding has led to the use of similar chemotherapy regimens in patients with pineoblastoma as part of a multimodality approach. Chemotherapy has been used to delay radiation therapy in very young children, for whom the long-term neurocognitive and developmental side effects of craniospinal irradiation (CSI) are a major concern. The importance of radiation therapy as a component of the initial treatment of supratentorial primitive neuroectodermal tumors (PNETs) is also supported by the German HIT-SKK87 and HIT-SKK92 protocols, as well as the Canadian pediatric brain tumor protocol

References

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