Pineal gland tumor

Pineal gland tumor Main page

Patient Information

Overview

Causes

Classification

Pineocytoma
Pineal teratoma
Pineal yolk sac tumor
Pineal choriocarcinoma
Pineal embryonal carcinoma
Pineal germinoma
Pineal gland cyst

Pathophysiology

Differentiating pineal gland tumor from Other Diseases

Differentiating features among different various Pineal Gland Tumors

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:  Fahimeh Shojaei, M.D., Sujit Routray, M.D. [2], Aditya Ganti M.B.B.S. [3]

Synonyms and keywords: Pineal gland tumors; Pineal gland cancer; Pineal gland cancers; Pineal gland neoplasm; Pineal gland neoplasms; Neoplasm of the pineal gland; Neoplasms of the pineal gland; Cancer of the pineal gland; Cancers of the pineal gland

## Overview

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The pineal gland is an endocrine gland that is located in the posterior aspect of the cranial fossa in the brain. The pineal gland is responsible for the secretion of melatonin hormone that regulates the in the circadian cycle sleep and wakefulness. The blood supply of the pineal gland is derived from the posterior cerebral artery from its choroidal branches. The internal cerebral vein drains the blood from the epiphysis cerebri. Histologically the gland consists of cells called pinealocytes. Several different tumors can arise from the pineal gland. Primary pineal cell tumors include pineocytoma, pineoblastoma, and mixed pineal tumors. Tumors that may occur in this region but are not necessarily pineal tumors include germinoma, non-germinoma (eg, teratoma, endodermal sinus tumor, embryonal cell tumor, choriocarcinoma, and mixed tumors), meningioma, astrocytoma, ganglioglioma, and dermoid cysts. Diagnosis of the type of tumor is crucial for treatment. The primary symptom of the tumor would be hydrocephalus. If the pineal gland invades the thalamus, it can cause weakness and loss of sensation in half of the body. Invasion of the hypothalamus would disrupt sleep, impede temperature and water regulation, and cause weight gain. An MRI is important when trying to see the location and size of the tumor. A biopsy is required to determine the type of tumor. Usually, a biopsy is done via a stereotactic or endoscopic procedure. Sometimes biomarkers are used to detect the presence of the tumor, and if these are found in the CSF and blood, then a biopsy might not be needed. Some of these chemicals are beta-human chorionic gonadotropin, carcinoembryonic antigen, and a-fetoprotein.

## Classification

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Pineal gland tumors are broadly divided into four subcategories. The various types of pineal gland tumors include:[1]

1\. Pineal parenchymal tumors: Pineal parenchymal tumors arise directly from the normal functional cells of the pineal gland, pineal parenchymal cells (pineocytes or their precursors), and they are distinct from other pineal gland neoplasms such as astrocytic and germ cell tumors. These tumors are formed after the embryological development of the pineal gland.
2\. Pineal germ cell tumors: They are tumors which arise from the embryological abnormalities. They are derived from the germ cells, including sex cells, of the pineal gland during the developmental process of the pineal gland.
3\. Astrocytoma of the pineal gland: They arise from the astrocytes, which are a particular kind of star-shaped, glial brain cells around the pineal gland.
4\. Pineal metastasis: Pineal metastasis is a cancer that has metastasized to the pineal gland from another location in the body.

Pineal gland tumors

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Pineal parenchymal tumors

Astrocytoma of the pineal gland

Germ cell tumors

Pineal metastasis

Pineocytoma

Pineal parenchymal tumor with intermediate differentiation

Papillary tumor of the pineal region

Pineoblastoma

Pineal germinoma

Pineal embryonal carcinoma

Pineal choriocarcinoma

Pineal yolk sac tumor

Pineal teratoma

## Pathophysiology

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### Normal Anatomy

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* The pineal gland is a small reddish-brown structure that derives its name from its pinecone-like shape.
* The pineal ranges in size from 10 to 14 mm; it is located in the midline, above the tentorium and superior colliculi and below the splenium of the corpus callosum and the vein of Galen, and is attached to the superior aspect of the posterior border of the third ventricle.
* The blood supply of the pineal gland is derived from the posterior cerebral artery from its choroidal branches.
* The internal cerebral vein drains the blood from the epiphysis cerebri.
* Histologically the gland consists of cells called pinealocytes and supporting cells.

Public Domain, https://commons.wikimedia.org/w/index.php?curid=378938

### Embryology

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* Pineal gland develops as a diverticulum in the diencephalic roof of the third ventricle during the second month of gestation.
* The mature gland is suspended from the pineal stalk from the posterior roof of the third ventricle.
* The pineal secretes melatonin, which is involved in diurnal rhythms.

### Pathogenesis

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* Due to the pineal gland's location, any tumor or cyst formation would lead to the compression of the aqueduct of Sylvius.
* The aqueduct of Sylvius allows the cerebrospinal fluid to circulate out.
* When there is a blockage in aqueduct of Sylvius by an abnormal pineal gland, the passage of the duct is blocked, and CSF pressure builds up, leading to hydrocephalus.
* Results in nausea, vomiting, visual changes, headaches, seizures, and memory changes.
* Increase in intracranial pressure can even be life-threatening, prompting emergency treatment.
* The hydrocephalus can be relieved by the placement of a VP shunt or ventriculostomy.
* Vision changes would also occur due to an involvement of the tectal region.
* The tectal region helps dictate eye movements.
* Fault in the tectal region causes double vision, an issue with focusing on objects, and eye movement impairment.
* The pineal gland can cause Parinaud syndrome due to the increasing size of the gland compressing the pretectal area and superior colliculi of the midbrain.
* Parinaud syndrome prevents a person from moving his or her eyes up and down.
* The thalamus can be affected, and if so, there can be disturbances on that side of the body which would result in weakness and loss of sensation.
* The tumor's effect on the hypothalamus will lead to weight gain, disruption of sleep, disruption of temperature control, and water regulation.
* Cerebellar involvement would result in motor impairment.
* If the tumor of the pineal gland is present in childhood, then endocrine dysfunctions can also result such as precocious pseudopuberty, diabetes insipidus, and a slowed growth rate.

## Laboratory Findings

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There are no specific laboratory findings associated with pineal gland tumors, however there are certain types of markers associated with diagnosis of germ cell tumors of pineal origin. Germ cell tumors include teratomas, embryonal carcinoma, yolk sac tumor, choriocarcinoma, and the mixed GCTs.

Type  | Oncoprotein

|

AFP  | β-HCG  | PLAP
Pure Germinoma  | \-  | \-  | \-
Mature Teratoma  | \-  | \-  |
Choriocarcinoma  | \-  | \+  | \-
Yolk sac tuumor  | \+  | \-  | \-
Embryonal carcinoma  | \-  | \-  | \+
Mixed GCT  | +/-  | +/-  | +/-

## Differentiating pineal gland tumor from Other Diseases

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Pineal gland tumormust be differentiated from other diseases that cause seizure, visual disturbance, and constitutional symptoms. For more information click here.

## Differentiating Features Among Various types of Pineal Gland Tumors

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Tumors  | Grade  | Pathalogic Features  | 5-year survival  | Cerebrospinal Fluid (CSF) Dissemination  | Imaging

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CT  | MRI
Pineocytoma |

* Grade I lesion

* Small, uniform, mature cells that resemble pineocytes
* Lobular architecture and pineocytomatous rosettes

* 86%–100%

* Rare

* Well demarcated, usually less than 3 cm, and iso- to hyperattenuating.

* Hypo- to isointense on T1-weighted images
* Hyperintense on T2-weighted images.

Pineal choriocarcinoma  |

* Grade IV

* Relatively rare, malignant, highly vascular neoplasm and accounts for a small proportion of all intracranial germ cell tumors.
* It is an aggressive tumor and has a propensity to metastasise systemically.
* Pure pineal choriocarcinoma tumors secrete β-HCG.[2]
* Characterized by presence of intimately related syncytiotrophoblasts and cytotrophoblasts without formation of definite placental type villi.

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* High

* Round, calcified, homogeneous, enhancing mass in the third ventricle associated with the dilation of the lateral and third ventricles and periventricular lucency.[3]

* Hyperintensity on T1-weighted images and signal drop-out and blooming on T2* sequences.[4]

Pineal embryonal carcinoma  |  |

* An aggressive tumor and has a propensity to metastasise systemically.
* A component of embryonal carcinoma is often found in mixed germ-cell tumours, in which case it is usually the most aggressive component, and dictates prognosis.
* Pure pineal embryonal carcinoma tumors do not secrete β-HCG or AFP.[5]
* Poorly differentiated, pleomorphic cells in cords, sheets, or papillary formation
* Indistinct cell borders
* Nucleoli \- key feature
* Vesicular nuclei (clear, empty appearing nuclei) - key feature
* Necrosis \- common
* Mitoses \- common
* Variable architecture:
* Solid (predominant in ~55% of cases)
* Glandular (predominant in ~17% of cases)
* Papillary (predominant in ~11% of cases)

|  | High  |  |
Pineal germinoma  |

* Grade II-III

* Pineal germinoma is the most common tumor of the pineal gland, but accounts for less than 1% of all the intracranial tumors.
* Pineal germinoma accounts for 50% of all the pineal gland tumors and the majority (80%) of the intracranial germ cell tumors.
* Uniform large, round cells with vesicular nuclei and clear or finely granular cytoplasm that is eosinophilic.
* Typically, the stroma contains lymphocytes and approximately 20% of patients have sarcoid-like granulomas.[6]

* 90%

* High

* Head CT scan may be diagnostic of pineal germinoma.
* Findings on CT scan suggestive of pineal germinoma include:[7][8]
* Obstructive hydrocephalus
* Large midline mass in the pineal region
* Hyperdense compared to normal brain
* Vivid contrast enhancement
* Calcification: usually representing "engulfed" pineal calcification

|  | T1  |

* Isointense to adjacent brain

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T2  |

* Isointense to adjacent brain

T1 with gadolinium contrast [T1 C+ (Gd)]  |

* Vivid homogenous enhancement

Diffuse weighted imaging [DWI]  |

* Restricted diffusion due to high cellularity

Pineal Parenchymal Tumor of Intermediate Differentiation  |

* Grade II or III

* Gross inspection, PPTID is similar in appearance to pineocytoma.
* It is a well-circumscribed lesion without evidence of necrosis.
* Histologic evaluation reveals diffuse sheets of uniform cells and the formation of small rosettes, with features intermediate between those of pineocytoma and those of pineoblastoma.
* Low to moderate levels of mitotic activity and nuclear atypia are seen.

* 39%–74%

* Rare

* No specific imaging findings

* No specific imaging findings
* Demonstrate high signal intensity on T2-weighted images and enhance on postcontrast images
* Cystic areas may also be seen

Pineoblastoma  |

* Grade IV

* Pineo-blastomas are highly cellular embryonal neoplasms that resemble other primitive neuroectodermal neoplasms of the central nervous system.
* Cells have scant cytoplasm and are arranged in diffuse sheets.
* Homer-Wright rosettes (neuroblastic differentiation) or Flexner-Wintersteiner rosettes (retinoblastic differentiation) may be seen, and hemorrhage or necrosis may be present.
* Infiltration into adjacent structures and craniospinal dissemination commonly occur

* 58%

* Most common cause of the death

* Lobulated, typically hyperattenuating mass, an appearance that reflects its highly cellular histologic features.

* Ill-defined enhancing pineal mass with resultant hydrocephalus

Papillary Tumor of the Pineal Region  |

* Grade II or III

* PTPRs are well-circumscribed lesions that can measure up to 5 cm and may have a cystic component.
* At histologic evaluation, they demonstrate an epithelial-like growth pattern, papillary features, rosettes, and perivascular pseudorosettes.
* The immunohistochemical findings help differentiate PTPR from other lesions in the pineal region, especially ependymoma and choroid plexus papilloma.

* 73%

* 75% times

* No specific imaging findings

* Well-circumscribed lesions with variable signal intensity on T1-weighted images, high signal intensity on T2-weighted images, and enhancement on postcontrast images.
* Cystic areas are commonly present.
* Hyperintensity on T1-weighted images has been described, which is hypothesized to be related to secretory inclusions containing protein or glycoprotein.

Germinoma  |

* Grade II

* Account for 1%–2% of all cranial neoplasms
* 65% of intracranial germinomas occur in the pineal region

* >79%

* The possibility of CSF seeding necessitates imaging evaluation of the entire neuroaxis

* Sharply circumscribed, hyperattenuating mass that engulfs the pineal calcifications

* Demonstrates a solid mass that may have cystic components.
* Germinomas are iso- to hyperintense to gray matter on T1- and T2-weighted images
* Avid, homogeneous enhancement on postcontrast images

Pineal Teratoma  |

* Grade III

* Mature teratoma reveals a lobulated neoplasm with a complex mixture of adult-type tissues from all three embryonic germ layers.
* Skin and skin appendages may be seen due to the ectodermal component.
* The mesoderm contributes to the presence of cartilage, bone, fat, and smooth and skeletal muscle.
* Respiratory or enteric epithelium arises from the endodermal component.
* Immature teratomas contain incompletely differentiated tissue elements that resemble fetal tissue.

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* Multiloculated, lobulated lesion with foci of fat attenuation, calcification, and cystic regions

* T1-weighted MR images may show foci of T1 shortening due to fat and variable signal intensity related to calcification.
* On T2-weighted images, the soft-tissue component is iso- to hypointense.

Pineal Cyst  |

* Grade II

* Pineal cysts occur in all age ranges but are most predominant in adults 40–49 years of age; studies demonstrate a female predominance.
* Their origin is debated, with some suggesting they result from degenerative changes in the gland.
* These lesions are typically asymptomatic and are usually 2–15 mm in size.
* Follow-up studies have indicated that these lesions remain stable in size over time.
* When they exceed 15 mm, patients may become symptomatic, typically with headache or visual changes.
* Intracystic hemorrhage (“pineal apoplexy”) and acute hydrocephalus rarely occur; resultant death has been reported

* 75% of pineal cysts remained stable during a period of 0.5–9.1 years.

* Rare

* No specific imaging findings

* Round or oval, thin-walled, and well-circumscribed.
* They typically demonstrate signal intensity similar to that of CSF on T1- and T2-weighted images

Epidermoid and Dermoid Cysts  |

* Grade II III

* The wall of epidermoid cysts is composed of simple stratified squamous epithelium, and the cyst contents consist of layers of keratinaceous debris, which impart a “pearly” appearance to the gross specimen.
* Dermoid cysts contain dermal appendages (hair follicles, sweat glands.
* Both lesions slowly expand over time and rupture can result in chemical meningitis, which may be fatal.

* N/A

* N/A

* Epidermoid cysts have low attenuation, similar to that of CSF.
* Dermoid cysts have a more variable appearance, and areas of low attenuation may be seen due to a lipid component—not due to fat, which is of mesodermal origin.
* Peripheral calcifications may be seen in both lesions.

* Epidermoid cysts are hypointense on T1-weighted images and hyperintense on T2-weighted images, with signal intensity similar to that of CSF.
* They insinuate into adjacent structures and encase nerves and blood vessels, making resection difficult.

Astrocytoma  |

* Grade I II III IV

* Uncommon.
* They derive from stromal astrocytes
* In the pineal region they arise from the splenium of the corpus callosum, the thalamus, or the tectum of the midbrain.
* Rarely, they may arise from the neuronal elements within the pineal gland.

* Grade 2
* 34% without treatment
* 70% with radiation therapy
* The prognosis is worst for these grade 4 gliomas.[9][10][11]
* Few patients survive beyond 3 years.

* Uncommon

* In low grade astrocytoma:
* Poorly demarcated mass
* Low density
* No inhancement inside the tumor
* In few cases we might see some calcification and cystic changes inside the mass
* In high grade astrocytoma:
* Poorly demarcated mass
* Low density
* There are partial enhancement inside the tumor mass

* Bulbous enlargement of the tectal plate is noted.
* The lesion is typically isointense on T1-weighted images
* Hyperintense on T2-weighted images with no to minimal enhancement on postcontrast images

Lipoma  |

* No Grading

* Abnormal differentiation of the meninx primitiva, which is the undifferentiated mesenchyme that surrounds the developing brain and normally develops into the leptomeninges and subarachnoid space.
* Lipomas represent malformations and not neoplasms.
* Blood vessels and nerves course through them, making resection difficult if required.

* Malignant transformation of lipomas into liposarcomas is very rare
* Liposarcomas are not produced from pre-existing benign lesions

* Uncommon

* Low attenuation, consistent with fat

* hyperintense on T1-weighted images with saturation on fat-saturated images

## References

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1. ↑ Pineal region mass. Dr Henry Knipe and Dr Frank Gaillard et al. Radiopaedia 2015. http://radiopaedia.org/articles/pineal-region-mass. Accessed on November 18, 2015
2. ↑ Intracranial choriocarcinoma. Frank Gaillard et al. Radiopaedia 2015. http://radiopaedia.org/articles/intracranial-choriocarcinoma. Accessed on December 7, 2015
3. ↑ Fujii, Toru; Itakura, Toru; Hayashi, Seiji; Komai, Norihiko; Nakamine, Hirokazu; Saito, Koji (1981). "Primary pineal choriocarcinoma with hemorrhage monitored by computerized tomography". Journal of Neurosurgery. 55 (3): 484–487. doi:10.3171/jns.1981.55.3.0484. ISSN 0022-3085.
4. ↑ MRI brain radiographic features of intracranial choriocarcinoma. Frank Gaillard et al. Radiopaedia 2015. http://radiopaedia.org/articles/intracranial-choriocarcinoma. Accessed on December 8, 2015
5. ↑ Intracranial embryonal carcinoma. Frank Gaillard et al. Radiopaedia 2015. http://radiopaedia.org/articles/intracranial-embryonal-carcinoma. Accessed on December 4, 2015
6. ↑ Histology of germinoma. Wikipedia 2015. https://en.wikipedia.org/wiki/Germinoma. Accessed on December 2, 2015
7. ↑ Reddy MP, Saad AF, Doughty KE, Armstrong D, Melguizo-Gavilanes I, Cheek BS; et al. (2015). "Intracranial germinoma". Proc (Bayl Univ Med Cent). 28 (1): 43–5. PMC 4264708. PMID 25552796.CS1 maint: Explicit use of et al. (link) CS1 maint: Multiple names: authors list (link) CS1 maint: PMC format (link)
8. ↑ CT radiographic features of intracranial germ cell tumors. Dr Ayush Goel and Dr Frank Gaillard et al. Radiopaedia 2015. http://radiopaedia.org/articles/intracranial-germ-cell-tumours. Accessed on December 2, 2015
9. ↑ See SJ, Gilbert MR (October 2004). "Anaplastic astrocytoma: diagnosis, prognosis, and management". Semin. Oncol. 31 (5): 618–34. PMID 15497115.
10. ↑ Korshunov A, Golanov A, Sycheva R (July 2002). "Immunohistochemical markers for prognosis of anaplastic astrocytomas". J. Neurooncol. 58 (3): 203–15. PMID 12187956.
11. ↑ Burger PC, Vogel FS, Green SB, Strike TA (September 1985). "Glioblastoma multiforme and anaplastic astrocytoma. Pathologic criteria and prognostic implications". Cancer. 56 (5): 1106–11. PMID 2990664.

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