Pineal parenchymal tumors

Pineal parenchymal tumors comprise a group of related tumors ranging from the relatively benign to the highly malignant. There are four types in the WHO classification:

• pineocytoma
  • 14-30% of pineal parenchymal tumors
  • mature well-differentiated tumor
  • WHO grade I
• pineal parenchymal tumor with intermediate differentiation
  • 20-62% of pineal parenchymal tumors
  • WHO grade II/III
• papillary tumor of the pineal region
  • yet to be graded but probably equivalent to WHO grade II/III
• pineoblastoma
  • 24-50% of pineal parenchymal tumors
  • malignant, primitive tumors
  • WHO grade IV

As you can tell from the proportions given above there is wide variation in the reported figures from series to series, which probably reflects the overall rarity of these tumors (and thus small series) and variability in the grading and terminology used.

Terminology

The term pinealoma was historically used to refer to both pineal parenchymal tumors and germinomas . This term has since fallen in popularity in the last several decades.