are relatively well circumscribed; however, the higher-grade astrocytomas demonstrate poorly defined margins (Figure 4).
The histopathological diagnosis of these two patients was pilocytic astrocytoma
Earlier research showed that most sporadic pilocytic astrocytomas
possess an abnormal form of a signaling protein known as BRAF.
Quality of life (QOL) assessments in children with juvenile pilocytic astrocytomas
(JPA) have shown that overall these children fare better than those with medulloblastoma or ependymoma or than those who receive chemotherapy, radiation therapy, or both.
Oncogenic RAF1 rearrangement and a novel BRAF mutation as alternatives to KIAA1549:BRAF fusion in activating the MAPK pathway in pilocytic astrocytoma
The two most common diagnostic errors surrounding pineal cyst are pilocytic astrocytoma
11,98,99) The glial component in these tumors varies but often resembles either a pilocytic astrocytoma
or an infiltrating glioma with astrocytic or oligodendroglial features.
The first is a cytologically bland and generally paucicellular astroglial proliferation with spindle, stellate, and piloid cells resembling pilocytic astrocytoma
Low-grade neoplasms, such as meningioma and pilocytic astrocytoma
, may also exhibit this type of spread, but at a slower rate of growth than most malignant tumors.
One case each of pigmented ganglioglioma,16 pilocytic astrocytoma
, and pleomorphic xanthoastrocytoma have been reported to date.
1-5] The most recent World Health Organization (WHO) classification (1993) separates astrocytic tumors into 2 main groups: the diffuse astrocytomas (WHO grades 2-4) and "other astrocytomas," the latter comprising a number of fairly distinct clinicopathologic entities, of which pilocytic astrocytoma
is by far the most common.
Although the morphologic features were consistent with pituicytoma, the differential diagnosis of a low-grade spindle cell lesion of the sella includes meningioma, schwannoma, spindle cell adenoma, and pilocytic astrocytoma