Pineocytoma

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

Synonyms and keywords: Pineocytomas; Pinealocytoma; Pinealocytomas; Pineal gland tumor; Brain tumor

Overview

Pineocytoma is a benign, slowly growing pineal parenchymal tumor.

Pathophysiology

Gross Pathology

On gross pathology, pineocytoma is characterized by solid, sometimes with focal areas of cystic change, 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 centre

• According to the WHO classification of tumors of the central nervous system, pineocytoma is classified into a WHO grade I tumor.

Immunohistochemistry

Pineocytoma is demonstrated by positivity to tumor markers such as:

• Synaptophysin
• Neuron-specific enolase

Gallery

• 

  _{Intermediate magnification micrograph of a pineocytoma. HPS stain.}

• 

  _{High magnification micrograph of a pineocytoma. HPS stain.}

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  _{Very high magnification micrograph of a pineocytoma. HPS stain.}

Differentiating Pineocytoma from other Diseases

Pineocytoma must be differentiated from:

• Pineal parenchymal tumor with intermediate differentiation
• Papillary tumor of the pineal region
• Pineoblastoma
• Pineal germinoma
• Pineal embryonal carcinoma
• Pineal choriocarcinoma
• Pineal yolk sac carcinoma (endodermal sinus tumor)
• Pineal teratoma
• Pineal cyst
• Astrocytoma of the pineal gland
• Meningioma near pineal gland
• Pineal metastasis
• Cavernoma in pineal region
• Aneurysm in pineal region

Epidemiology

Age

• Pineocytoma is a rare disease that tends to affect all the age groups, most commonly in the second decade of life.

Gender

• Pineocytoma affects men and women equally.

Natural History, Complication and Prognosis

Natural History

If left untreated, patients with pineocytoma may progress to develop seizures, obstructive hydrocephalus, local recurrence, and CSF metastasis.

Complications

Common complications of pineocytoma include:

• Local recurrence
• CSF metastasis

Prognosis

Prognosis is generally excellent, and the 5-year survival rate of patients with pineocytoma is approximately 86%.

History and Symptoms

History

When evaluating a patient for pineocytoma, you should take a detailed history of the presenting symptom (onset, duration, and progression), other associated symptoms, and a thorough family and past medical history review.

Symptoms

• The clinical presentation of pineocytoma is mainly from the obstructive hydrocephalus secondary to compression of the tectum of the midbrain and obstruction of the aqueduct.
• Symptoms of pineocytoma include:

• Headaches
• Nausea
• Vomiting
• Seizures
• Sleepiness
• Irritability
• Personality changes
• Double vision
• Trouble coordinating motor movements
• Difficulty walking
• Slowed growth

Physical Examination

• Compression of the superior colliculi can also lead to a characteristic gaze palsy, known as Parinaud syndrome.
• Common physical examination findings of pineocytoma include:

===HEENT===

• Bulging soft spots (fontanelles)
• Eyes that are constantly looking down (sunsetting sign)
• Deficiency in upward-gaze
• Pupillary light-near dissociation (pupils respond to near stimuli but not light)
• Convergence-retraction nystagmus

===Neurological===

• Mental retardation
• Muscle spasms
• Loss of bladder control
• Ataxia

CT

• Head CT scan may be diagnostic of pineocytoma.
• Findings on CT scan suggestive of pineocytoma include a mass of intermediate density similar to the adjacent brain with peripheral calcifications.

Gallery

• 

  _{Different patterns of pineal calcification: Exploded calcification of tumors of pineal cell origin and engulfed calcification by germinomas.}

• 

  _{Single image following biopsy and third ventriculostomy demonstrates a pineal region soft tissue mass. A small amount of blood is seen in the occipital horn on the right. Ventricles remain dilated.}

MRI

• Brain MRI may be diagnostic of pineocytoma.
• Features on MRI suggestive of pineocytoma include:

MRI component	Findings
T1	Isointense to brain parenchyma
T2	Solid components are isointense to brain parenchyma Areas of cystic change Sometimes the majority of the tumor is cystic
T1 with gadolinium contrast	Solid components vividly enhance

Treatment

The mainstay of therapy for pineocytoma is surgery.

References

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