Pilocytic astrocytoma

Gutmann DH, Donahoe J, Brown T, James CD, Perry A (2000) Loss of neurofibromatosis 1 (NFl) gene expression in NFl-associated pilocytic astrocytomas. Neuropathol Appl Neurobiol 26 361-367... 

Pilocytic means composed of hair cells, which is a major feature of the pilocytic astrocytoma. Parallel bundles of elongated, fibrillar, cytoplasmic processes resemble mats of hair (see Fig. 20.12A). These hairlike processes contain large amounts of glial fibrils, which stain well with immunoperoxidase for GFAP (see Table 20.5). 

Most, but not all, pilocytic astrocytomas occur in children or young adults. They are most abundant in the posterior fossa and around the third ventricle, thalamus, hypothalamus, neurohypophysis, and optic nerve. Cerebral hemispheric pilocytic astrocytomas are less common, but it is important to recognize them to ensure appropriate treatment. ... 

Pilocytic astrocytoma Hypercellularity hairllke fibrillarity Rosenthal fibers microcysts GFAP (+) S-100 alpha B-crystalline Cerebellum thalamus/ hypothalamus optic nerve CNS... 

Eosinophilic granular bodies (EGB) are eosinophilic droplets of protein often found in pilocytic astrocytomas. 

Observations of subtypes of S-100 protein suggest that they distinguish pilocytic astrocytomas from WFiO grade II to IV astrocytomas. Pilocytic astrocytomas do not overexpress p53 protein. They tend to lack EGFR abnormalities. " These features may have future diagnostic use. 

Fibrous meningiomas are firm tumors composed of spindle cells (see Table 20.5). They resemble schwannomas, solitary fibrous tumors, fibrillary astrocytomas, and pilocytic astrocytomas. Fibrous meningiomas contain parenchymal collagen, often in large, pink bundles on H E staining that distinguish them from astrocytomas. ... 

Neurofibroma may occur as a sporadic tumor or as part of the dominantly inherited tumor syndrome called von Recklinghausen disease or neurofibromatosis-1 (NF-l).i Plexiform neurofibromas are multiple swollen fascicles that are associated with NF-1. Other nervous system signs of NF-1 are more than one neurofibroma, optic nerve glioma (more appropriately called optic nerve pilocytic astrocytoma), and malignant peripheral nerve sheath tumor with glandular or rhabdomyoblastic regions. ... 

Cystic astrocytoma Wall of pilocytic astrocytoma GFAP(-l-) S-100 (-I-) Cerebellum CNS... 

Cheng Y, Pang JC, Ng HK, et al. Pilocytic astrocytomas do not show most of the genetic changes commonly seen in diffuse astrocytomas. Histopathology. 2000 37 437-444. 

Forsyth PA, Shaw EG, Scheithauer BW, et al. 51 cases of supratentorial pilocytic astrocytomas A clinicopathologic, prognostic, and flow cytometric study. Cancer. 1993 72 1335-1342. 

Coakley KJ, Huston J, Scheithauer BW, et al. Pilocytic astrocytomas Well-demarcated magnetic resonance appearance despite frequent infiltration histologically. Mayo Clin Proc. 1995 70 747-751. 

Clark GB, Henry JM, McKeever PE. Cerebral pilocytic astrocytoma. Cancer. 1985 56 1128-1133. 

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