Pineocytoma Pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Sujit Routray, M.D. [2] Homa Najafi, M.D.[3]

Overview

The exact pathogenesis of [disease name] is not fully understood.

OR

It is thought that [disease name] is the result of / is mediated by / is produced by / is caused by either [hypothesis 1], [hypothesis 2], or [hypothesis 3].

OR

[Pathogen name] is usually transmitted via the [transmission route] route to the human host.

OR

Following transmission/ingestion, the [pathogen] uses the [entry site] to invade the [cell name] cell.

OR

[Disease or malignancy name] arises from [cell name]s, which are [cell type] cells that are normally involved in [function of cells].

OR

The progression to [disease name] usually involves the [molecular pathway].

OR

The pathophysiology of [disease/malignancy] depends on the histological subtype.

Pathophysiology

Physiology

The normal physiology of [name of process] can be understood as follows:

Pathogenesis

• The exact pathogenesis of [disease name] is not completely understood.

OR

• It is understood that [disease name] is the result of / is mediated by / is produced by / is caused by either [hypothesis 1], [hypothesis 2], or [hypothesis 3].
• [Pathogen name] is usually transmitted via the [transmission route] route to the human host.
• Following transmission/ingestion, the [pathogen] uses the [entry site] to invade the [cell name] cell.
• [Disease or malignancy name] arises from [cell name]s, which are [cell type] cells that are normally involved in [function of cells].
• The progression to [disease name] usually involves the [molecular pathway].
• The pathophysiology of [disease/malignancy] depends on the histological subtype.

Genetics

[Disease name] is transmitted in [mode of genetic transmission] pattern.

OR

Genes involved in the pathogenesis of [disease name] include:

• [Gene1]
• [Gene2]
• [Gene3]

OR

The development of [disease name] is the result of multiple genetic mutations such as:

• [Mutation 1]
• [Mutation 2]
• [Mutation 3]

Associated Conditions

Conditions associated with [disease name] include:

• [Condition 1]
• [Condition 2]
• [Condition 3]

Gross Pathology

On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

Microscopic Pathology

On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

Pathophysiology

Pathogenesis

• 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.

Gross Pathology

On gross pathology, pineocytoma is characterized by solid, sometimes with focal areas of cystic change, gray, well-circumscribed mass with or without hemorrhage.

Microscopic Pathology

On microscopic histopathological analysis, pineocytoma is characterized by:

• Cytologically benign cells (uniform size of nuclei, regular nuclear membrane, light chromatin)
• Pineocytomatous/neurocytic rosette, which is an irregular circular/flower-like arrangement of cells with a large meshwork of fibers (neuropil) at the center.

Intermediate magnification micrograph of a pineocytoma. HPS stain.

Immunohistochemistry

Pineocytoma is demonstrated by positivity to tumor markers such as:

• Synaptophysin
• Neuron-specific enolase
• GFAP
• Chromogranin A
• PLAP
• Ki-67
• Beta tubulin III