Tumors of the Pineal Region



Tumors of the Pineal Region








Tumor Types

Pineocytoma

Pineal parenchymal tumor of intermediate differentiation (PPTID)

Papillary tumor of the pineal region (PTPR)

Pineoblastoma


Pineocytoma

Definition: Pineocytoma is a well-differentiated pineal parenchymal tumor comprised of uniform cells forming large pineocytomatous rosettes and/or of pleomorphic cells showing gangliocytic differentiation. It is a WHO grade I tumor with no malignant potential or dissemination.

Epidemiology: This accounts for <1% of all intracranial neoplasms and 27% of pineal neoplasms.

Affected age group: The tumor can occur in any age but most frequently affects adults, with a mean age of 43 years; there is a female predominance, with a female-to-male ratio of 1:0.6.

Molecular and genetic profile: Cell of origin is likely the pinealocyte, a cell with photosensory and neuroendocrine functions. It is associated with immunoexpression of cone-rod homeobox (CRX) (a transcription factor involved in the development and differentiation of pineal cell lineage) and acetylserotonin methyltransferase (ASMT) (a critical enzyme for synthesis of melatonin, which is a hormone produced by the pineal gland). No syndromic associations or genetic susceptibilities are known.

CSF markers: None.

Clinical features and standard therapy: Surgical resection is the definitive treatment without adjuvant radiotherapy or chemotherapy.

Prognosis: The 5-year survival rate ranges from 86% to 91%, and the most important prognostic marker is the extent of surgical resection.


Imaging

The hallmark of pineocytoma is a lobulated solid mass with or without cystic or calcific component, usually <3 cm, which may cause obstructive hydrocephalus. The cystic component may be the dominant feature with minor solid tumor tissue.