Pilocytic astrocytoma (WHO Grade I)
- This lesion is solid looking along with areas of microcystic pattern
- Loose fibrillary architecture formed by ovoid to elongated cells with thin cytoplasmic hair-like (piloid) processes.
- Some areas shows rosenthal fibers (pinkish-red, irregular fibers)
- Few aggregates of eosinophilic granular bodies
Points of Pathoclinics:
- Most important differentials is Low grade diffuse astrocytoma. Features like thin hair like processes, rosenthal fibers, and eosinophilic granular bodies favors pilocytic astrocytoma. Pilocytic astrocytoma is well circumscribed and contrast enhancing lesion along with cystic changes on radiology in contrast to low grade astrocytoma.
- Reactive gliosis/piloid gliosis are also close differentials, which usually arise around the cystic lesion like ameloblastomas, hemangioblastomas. Reactive gliosis/piloid gliosis are relatively hypocellular, with abundant rosenthal fibres. Diagnosis should be based on appropriate radiology findigns.