Astrocytoma diagnostic study of choice

There is no single diagnostic study of choice for the diagnosis of astrocytoma, but astrocytoma can be diagnosed based on clinical presentation, imaging studies and biopsy results.The various investigations must be performed in the following order: Physical examination, imaging study (MRI is the preferred imaging technique) and tumor biopsy.

There is no single diagnostic study of choice for the diagnosis of astrocytoma, but astrocytoma can be diagnosed based on clinical presentation, imaging studies and biopsy results.

Investigations:

• Among the patients who present with clinical signs of intracranial mass, the tumor biopsy is the most specific test for the diagnosis.
• Among the patients who present with clinical signs of intracranial mass, the imaging study is the most sensitive test for diagnosis.

The following findings on performing MRI are confirmatory for astrocytoma:^[1][2]

• Low grade astrocytoma (pilocytic and diffuse astrocytoma)
  • T1: Decreased resonance in comparison to surrounding brain tissue
  • T2: Increased resonance in comparison to surrounding brain tissue
• High grade astrocytoma
  • Anaplastic astrocytomas
    • Hypointense T1
    • Hyperintense T2
    • There might be some contrast enhancement and edema
  • Glioblastoma multiform
    • Irregular ring-nodular enhancing lesions
    • Central necrosis
    • Surrounding vasogenic edema

For more information on MRI findings, click here.

The following findings on performing biopsy are confirmatory for astrocytoma:

Pathological findings diagnostic of astrocytoma include:^[3][4][5]

• Pilocytic:
  • Cells appearance is normal and growth rate is slow.
  • Biphasic pattern (dense fibrillar tissue within loose myxoid tissue)
  • Calcification
  • Vascular hyalinization
  • Nested fibrotic pattern
• Diffuse:
  • There might be some atypical cells inside tumor.
  • Mitosis rate is relatively slow.
  • Diffusely infiltrate neuropil
  • Poorly defined cytoplasm
• Anaplastic:
  • Tumor cells are pleomorphic and malignant
  • High mitosis rate
  • Hyperchromatosis
  • Prominent small vessels
• Glioblastoma:
  • Pleomorphic cells
  • Naked nuclei
  • Multi-focal necrosis
  • Pseudopalisading pattern
  • Scattered pyknotic nuclear debris in the center
  • Micro-vascular proliferation
  • Vascular thrombi

For more information on biopsy findings, click here.

The various investigations must be performed in the following order:

• Physical examination
• Imaging study (MRI is the preferred imaging technique)
• Tumor biopsy

There are no established criteria for the diagnosis of astrocytoma.

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