Pineal gland

The pineal gland is thingy that is most noted for the fact that it calcifies with age.

Normal histology

See Neurohistology#Pineal gland.

• Cellular.

Overview

Tumours:

• Primary pineal tumours ~15% of (pineal) tumours - benign to malignant:
  • Pineocytoma.
  • Pineal parenchymal tumor of intermediate differentiation.
  • Pineoblastoma.
• Germ cell tumours:
  • Germinoma ~ 50% of (pineal) tumours.
  • Teratoma ~ 15% of tumours.
  • Choriocarcinoma ~ 5% of tumours.
• Others:
  • Direct invasion/extension from surrounding structures (astrocytomas).
  • Metastases.
  • Lipomas.
  • Meningiomas.

Primary pineal tumours

Range from benign to malignant.

Pineocytoma

General

• Benign tumour of the pineal gland.
  • WHO Grade I.

Microscopic

Features:

• Cytologically benign cells (uniform size of nuclei, regular nuclear membrane, light chromatin).
• Pineocytomatous/neurocytic rosette = (irregular) rosette with a large meshwork of fibers (neuropil) at the centre.
  • Similar to Homer-Wright rosette... but:
    1. Neuropil centre is larger in pineocytoma.
    2. Edge of neuropil meshwork irregular.

Notes:

• Rosette = circular/flower-like arrangement of cells.

Images

• 

  Pineocytoma - intermed. mag. (WC)

• 

  Pineocytoma - high mag. (WC)

• 

  Pineocytoma - very high mag. (WC)

• www:
  • Pineocytoma with neuronal differentiation (upmc.edu).

IHC

• Synaptophysin +ve.
• Chromogranin A -ve.
• NSE +ve (cytoplasmic + nuclear).
• GFAP -ve.
  • +ve in gliomas.
• PLAP -ve.
  • Usu. +ve in germ cell tumours.
• Ki-67.

Another ref.:

Pineoblastoma

General

• Rare.
• Malignant.
• Males > females.
• Children & young adults.

Microscopic

Features:

• Hypercellular.
• Mitoses.
• Nuclear atypia.

DDx:

• Glioblastoma.

Images:

• Pineoblastoma - several images (upmc.edu).

IHC

• GFAP -ve/+ve.

See also

• Neuropathology.
• CNS tumours.