Pineal Region Tumors Onc28 Pineal Region Tumors, Pineal Parenchymal Tumors



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Pineal Region Tumors Onc28 ()

Pineal Region Tumors, Pineal Parenchymal Tumors

Last updated: September 5, 2017



Terminology 2

Epidemiology 2

Etiology 3

Classification, Pathology 3

Pineal Parenchymal Tumors 3

Pineocytoma 4

Pineoblastoma 8

Pineal parenchymal tumour of intermediate differentiation 15

Papillary tumour of pineal region 18

Gliomas 22

Miscellaneous 22

Benign pineal cysts 22

Clinical Features 24

Diagnosis 25

Treatment 31

Biopsy 32

Surgery 32

Approaches 32

Patient positions 39

Complications 42

Postoperatively 43

Radiotherapy 45

Chemotherapy 45

Radiosurgery 46



Prognosis 46

Pineocytomas 46

Pineoblastoma 47

PPTID 47


Papillary tumor of pineal region 47

Pineal gland region has greatest variety of tumor types among CNS!

  • pineal gland is neuroendocrine transducer that synchronizes hormonal release (LH, FSH) with light-dark cycle by means of its sympathetic input from retina.

  • pinealocyte - pineal parenchymal cell (specialized neuron); pinealocyte receives direct inervation by peripheral sympathetic nervous fibers!

basics of pineal gland → further see p. 2717-2718 (endocrine system) >>

anatomy and embryology of pineal region → see p. A110 >>

Terminology

Pineal region tumor is preferred general term; individual tumor's histology is used for specificity (e.g. astrocytoma of pineal region).


  • term pinealoma was originally used by Krabbe but is now obsolete.

Epidemiology

see also individual tumors below

  • ≤ 1.0% of intracranial tumors in adults (3.0-8.0% in children)

Etiology

      1. transformation of pinealocytes

      2. transformation of pineal astroglia.



  • no specific genetic mutations have been associated.

Classification, Pathology

  1. Germ cell tumors (40-65%)

  2. Pineal parenchymal tumors (17%)

  3. Glial cell tumors (15-25%)

  4. Miscellaneous tumors and cysts:

metastasis, meningioma, hemangioblastoma, choroid plexus papilloma, chemodectoma, adenocarcinoma, lymphoma, vascular lesions (AVMs, cavernous malformations, vein of Galen malformation), benign pineal cysts.

  • each category has continuum from benign to malignant; mixed tumors (of more than one cell type) also occur.

Pineal Parenchymal Tumors

  • 14-27% of pineal region tumors

  • term pinealomas is obsolete;

  • from pinealocytes - cells with photosensory and neuroendocrine functions

  • males = females

  • most frequent in 1st decade

Pineocytoma

(WHO grade I)



Epidemiology

  • 14-60% of pineal parenchymal tumors.

  • mainly in adults - mean age: 38 years (but occur throughout life); no sex predilection.



Macro

  • slowly growing, grossly demarcated (well-circumscribed).

  • degenerative changes (cysts, foci of haemorrhage) may be present.

  • typically remain localized to pineal area where they compress adjacent structures (cerebral aqueduct, brain stem,cerebellum); protrusion into posterior third ventricle is often seen.

  • no pineocytomas have been shown to metastasize!

Micro

  • moderately cellular.

  • relatively small, uniform, homogeneously eosinophilic, mature cells resembling pineocytes.

  • grows in sheets or ill-defined lobules.

  • conspicous processes - short, often ending in club-shaped expansions.

  • mitotic figures are lacking in all but occasional large specimens (< 1/10 HPF)

  • often forming large pineocytomatous rosettes - anucleate centres being composed of abundant, delicate tumour cell processes resembling neuropil.

Immunohistochemistry

  • strong immunoreactivity for synaptophysin, NSE and NFP.

  • photosensory differentiation is associated with immunoreactivity for retinal S-antigen and rhodopsin.

  • variable staining for other neuronal markers (class III ß-tubulin, tau protein, PGP 9.5, chromogranin, serotonin)

  • in tissue culture, capable of synthesizing serotonin and melatonin.

Electron microscopy
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