Pilocytic astrocytoma or juvenile pilocytic astrocytoma or cystic cerebellar astrocytoma (and its variant juvenile pilomyxoid astrocytoma) is a neoplasm of the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 that occurs more often in children and young adults (in the first 20 years of life). They usually arise in the cerebellum

Cerebellum

The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...

, near the brainstem, hypothalamic region, or the optic chiasm

Optic chiasm

The optic chiasm or optic chiasma is the part of the brain where the optic nerves partially cross...

, but they may occur in any area where astrocyte

Astrocyte

Astrocytes , also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord...

s are present, including the cerebral hemispheres and the spinal cord

Spinal cord

The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...

. These tumors are usually slow growing. The neoplasms are associated with the formation of a single (or multiple) cyst

Cyst

A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...

(s), and can become very large.

The pilocytic astrocytoma is, in general, considered a benign

Benign

A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...

 tumor. It is often cystic, and, if solid, it tends to be well-circumscribed. It is characteristically a contrast-enhancing tumor by current imaging investigations (e.g., CT scan, MRI)

Juvenile pilocytic astrocytoma is associated with neurofibromatosis

Neurofibromatosis

Neurofibromatosis is a genetically-inherited disorder in which the nerve tissue grows tumors that may be benign or may cause serious damage by compressing nerves and other tissues...

 type 1 (NF1), and optic gliomas are among the most frequently encountered tumors in patients with this disorder.

It is classified as Grade 1 Astrocytoma

Astrocytoma

Astrocytomas are a type of neoplasm of the brain. They originate in a particular kind of glial-cells, star-shaped brain cells in the cerebrum called astrocytes. This type of tumor does not usually spread outside the brain and spinal cord and it does not usually affect other organs...

.

Symptoms

Children affected by pilocytic astrocytoma can present with different symptoms that might include failure to thrive (lack of appetite) headache, nausea, vomiting, irritability, difficulty to coordinate movements and visual complaints (including nystagmus). The complaints may vary depending on the location and size of the neoplasm. The most common symptoms are associated with increased intracranial pressure due to the size of the neoplasm.

Occurrence

According to a Dutch source juvenile pilocytic astrocytoma occurs at a rate of 2 in 100,000 people. Most affected are children ages 5–14 years.

Tumors of the optic pathway account for 3.6-6% of pediatric brain tumors, 60% of which are juvenile pilocytic astrocytomas. Astrocytomas account for 50% of pediatric primary central nervous system tumors. About 80-85% of cerebellar astrocytomas are juvenile pilocytic astrocytomas.
Quoted from emedicine

Diagnosis

Usually—depending on the interview of the patient and after a clinical exam which includes a neurological exam, and an ophthalmological exam—a CT scan and or MRI scan will be performed. A special dye may be injected into a vein before these scans to provide contrast and make tumors easier to identify. The neoplasm will be clearly visible.

If a tumor is found, it will be necessary for a neurosurgeon to perform a biopsy on it. This simply involves the removal of a small amount of tumorous tissue, which is then sent to a (neuro)pathologist for examination and staging. The biopsy may take place before surgical removal of the tumor or the sample may be taken during surgery.

Visual aspect

Macroscopically, an astrocytoma is a mass that looks well-circumscribed and has a large cyst. The neoplasm may also be solid. Under the microscope, the tumor is seen to be composed of bipolar cells with long "hairlike" GFAP

Glial fibrillary acidic protein

Glial fibrillary acidic protein is an intermediate filament protein that was thought to be specific for astrocytes in the central nervous system . Later, it was shown that GFAP is also expressed by other cell types in CNS, including ependymal cells...

-positive processes, giving the designation "pilocytic" (that is, made up of cells that look like fibers when viewed under a microscope). There is often presence of Rosenthal fiber

Rosenthal fiber

A Rosenthal fiber is a thick, elongated, worm-like or "corkscrew" eosinophilic bundle that is found on H&E staining of the brain in the presence of long standing gliosis, occasional tumors, and some metabolic disorders.-Associated conditions:...

s, eosinophilic

Eosinophilic

Eosinophilic refers to the staining of certain tissues, cells, or organelles after they have been washed with eosin, a dye.Eosin is an acidic dye; thus, the structure being stained is basic....

granular bodies and microcysts.

Treatment

Surgery is often the treatment of choice. Total resection is often possible; however, the location could prohibit access to the neoplasm and lead to incomplete or no resection at all. Removal of the tumor will generally allow functional survival for many years. The five-year survival has been reported to be over 90% with well-resected tumors. In particular for pilocytic astrocytomas (that are commonly indolent bodies that may permit normal neurologic function) surgeons may decide to monitor the neoplasm's evolution and postpone surgical intervention for some time. However, left unattended these tumors may eventually undergo neoplastic transformation.

Some articles mention ultrasonic aspiration as a minimal invasive technique for solid neoplasms.

Because of the age of people diagnosed with pilocytic astrocytoma, the treating medical team will often try to avoid radiotherapy and chemotherapy in order avoid damage to the developing brain. There is evidence in literature to suggest that the careful use of chemotherapy and/or radiation therapy may be useful as a complementary treatment in case of incompletely resection of the neoplasm.

Side effects

Children with cerebellar pilocytic astrocytoma may experience side effects related to the tumor itself and related to the treatment.

• Symptoms related to increased pressure in the brain often disappear after surgical removal of the tumor.
• Effects on coordination and balance improved and might progressively (to completely) disappear as recovery progresses.
• Steroid-treatment is often used to control tissue swelling that may occur pre- and post-operatively.

Epileptic seizures

Any person undergoing brain surgery may suffer from epileptic seizures.

• Medication is administered to minimize the occurrence of seizures.

Parents of children after surgery should be made aware of this fact and should be prepared to take adequate action in case of the seizure (see brain tumor)

Chemotherapy

Common side effects of chemotherapy includes nausea, vomiting and decreased blood counts (i.e. anemia).

• Anti-emetics (anti-nausea) medications can help these side-effects.
• Occasionally, children receiving chemotherapy will need extra transfusion(s) of red blood cells and/or platelets to replace these cells, since the toxicity of the therapy temporarily affects the ability to produce these blood components. Also white blood cells are affected but never given by transfusion; instead a medication will assist the body in producing white blood cells.

Radiation therapy

Juvenile pilocytic astrocytomas that are initially characterized according to WHO grade I have been found to undergo malignant transformation following radiation treatment.

Radiation therapy may cause swelling related to tissue inflammation.

• This inflammation may lead to symptoms like headache or difficulty with coordination and may be treated with oral medication.

Expected outcome after treatment

• Grade I pilocytic astrocytoma and cerebellar gliomas are not associated with reccurance after complete ressection.
• Grade II astrocytomas and cerebellar gliomas are more likely to recur after surgical removal.

• How to respond to progressive or recurrent disease?

The recommended course of action according to different literature sources is to monitor and reattempt a complete surgical removal. In cases of progressive/recurrent disease or when maximal surgical removal has been achieved, chemotherapy and/or radiation therapy will be considered by the medical team.

Mortality

After total resection the 10-year survival rate is 90%. After incomplete resection, the 10-year survival rate is as high as 45%. Morbidity is determined by the location (and accessibility) of the tumor and with the associated complications for a tumor resection.

External links

• JPA Boston Children's hospital Juvenile Pilocytic Astrocytoma
• UWO University of Western Ontario Neurology pocketbook
• Pilocytic Astrocytoma MedPix Medical Image Database
• UC
• fightJPA - An Organization Dedicated to Funding Research into Juvenile Pilocytic Astrocytoma
• PA Braintumor.org - Pilocytic Astrocytoma
• Pathology Staging of JPA
• PLGA Pediatric Lowgrade Astrocytoma's