Department of Pathology, University of Oklahoma Health Sciences Center

Pilocytic Astrocytoma

      Click on thumbnails to see enlarged pictures.

• Panel A: "Pilo" means hair. The tumor cells of pilocytic astrocytoma have hair like long process. This property is well illustrated in this photo.
• Panel B: Typically, pilocytic astrocytoma has alternating densely packed areas (d) and loosely packed areas (L).
• Panel C: Rosenthal material (fiber) is a common feature in pilocytic astrocytoma. The presence of Rosenthal material (fiber) is an indication of chronic gliotic process and can be seen in slowly growing astrocytic tumors such as pilocytic astrocytoma and also non-neoplastic, reactive gliotic process. Although it is common, it is not specific for pilocytic astrocytoma.
• Panel D (Jones stain): Pilocytic astrocytoma typically contains this type of glomeruloid tangles of thin-walled blood vessels. They must not be mistaken as endothelial proliferation that are seen in high-grade glial neoplasm. The complicated structure is best demonstrated by Jones stain that the basement membrane of blood vessels dark brown.

For Comment: KarMing-Fung@ouhsc.edu