Pleomorphic xanthoastrocytoma
Synonyms and keywords: Pleomorphic xanthoastrocytomas; PXA

# Overview
Pleomorphic xanthoastrocytoma is a type of rare, low-grade astrocytoma (WHO Grade II) found among young patients who typically present with temporal lobe epilepsy.

# Pathophysiology

## Pathogenesis
- Pleomorphic xanthoastrocytoma is formed through the abnormal mitosis of the astrocytes.

## Gross Pathology
- On gross pathology, polymorphic xanthoastrocytoma is characterized by a well-circumscribed mass, often with a cystic component and a superficially situated mural nodule.
- Polymorphic xanthoastrocytomas are almost invariably (98%) located supratentorially, typically involving the cortex and overlying leptomeninges. Approximately half are located in the temporal lobe.
- They are found commonly in the area of the temporal lobe, frontal lobe, or superior to the parietal lobe. In about 20% of cases, more than one lobe is involved.

## Microscopic Pathology
- On microscopic histopathological analysis, polymorphic xanthoastrocytoma is characterized by:
- Ill-defined margins
- Spindle cells, polygonal cells, multi-nucleated cells, and lipid laden xanthomatous astrocytes
- Pleomorphic nuclei
- No endothelial proliferation or necrosis

## Immunohistochemistry
- On immunohistochemistry, polymorphic xanthoastrocytoma is characterized by a positive GFAP tumor marker.

# Differentiating Pleomorphic Xanthoastrocytoma from other Diseases
Pleomorphic xanthoastrocytoma must be differentiated from:
ABBREVIATIONS
CNS=Central nervous system, AV=Arteriovenous, CSF=Cerebrospinal fluid, NF-2=Neurofibromatosis type 2, MEN-1=Multiple endocrine neoplasia, GFAP=Glial fibrillary acidic protein, HIV=Human immunodeficiency virus, BhCG=Human chorionic gonadotropin, ESR=Erythrocyte sedimentation rate, AFB=Acid fast bacilli, MRA=Magnetic resonance angiography, CTA=CT angiography

# Epidemiology and Demographics

## Prevalence
- Pleomorphic xanthoastrocytoma constitutes approximately 1% of all primary brain tumors.

## Age
- Pleomorphic xanthoastrocytoma is a rare disease that tends to affect children and young adults.
- The median age at diagnosis is 26 years.

# Natural History, Complications and Prognosis

## Natural History
If left untreated, patients with pleomorphic xanthoastrocytoma may progress to develop seizures, focal neurological deficits, and malignant transformation to either WHO grade III lesion or glioblastoma multiforme.

## Complication
Common complications of pleomorphic xanthoastrocytoma include:
- Local recurrence
- Malignant transformation (WHO grade III astrocytoma or glioblastoma multiforme)

## Prognosis
Prognosis is generally good, and the 5-year survival rate of patients with pleomorphic xanthoastrocytoma is approximately 70-80%.

# Symptoms
Symptoms of fibrillary astrocytoma include:
- Elevated intracranial pressure
- Headaches
- Nausea
- Vomiting
- Temporal lobe epilepsy
- Seizures with or without aura
- Amnesia
- Loss of consciousness
- Abnormal auditory sensations (sound or tune)
- Abnormal gustatory sensation (taste)
- Abnormal olfactory sensation (smell that is not truly present)
- Dysphoria or euphoria
- Motionless staring, automatic movements of the hands or mouth, inability to respond to others, unusual speech, or unusual behavior
- Neurological symptoms
- Hemiparesis
- Changes in behavior

# CT
Head CT scan is helpful in the diagnosis of pleomorphic xanthoastrocytoma. On CT scan, pleomorphic xanthoastrocytoma is characterized by:
- Iso- or hypoattenuating mass
- Calcification
- Vivid enhancement on contrast administration

# MRI
Brain MRI is helpful in the diagnosis of pleomorphic xanthoastrocytoma. On MRI, pleomorphic xanthoastrocytoma is characterized by:

# Biopsy
Biopsy of pleomorphic xanthoastrocytoma tumor, taken through a needle during a simple surgical procedure, helps to confirm the diagnosis.

# Other Diagnostic Studies

## Electroencephalogram
- Electroencephalogram (EEG) is performed among patients of pleomorphic xanthoastrocytoma to record any abnormal electrical activities (seizures).

## Digital Subtraction Angiography
- Digital subtraction angiography (DSA): Despite vivid enhancement, pleomorphic xanthoastrocytomas are usually avascular on angiography.

## Positron Emission Tomography
- F-18 FDG PET images of pleomorphic xanthoastrocytoma demonstrate markedly decreased accumulation of -fluorodeoxyglucose (glucose hypometabolism).

# Treatment
- The predominant therapy for pleomorphic xanthoastrocytoma is surgical resection. Adjunctive radiation may be indicated in cases of incompletely resected or recurrent tumors.
- Complete surgical resection is often possible. However, the best choice of treatment will depend on many individual factors including:
- Patient's medical history and overall health condition
- Type, location, and size of the tumor
- Patient's age
- Aggressiveness of the tumor
- If surgery is performed and the tumor is completely resected, further treatment may not be required.