Robbins Flashcards
most common group of primary brain tumors
Gliomas
two major categories of astrocytic tumors
diffusely infiltrating astrocytomas (WHO grade II to IV) and the more localized astrocytomas (ie. pilocytic astrocytoma, WHO grade I)
Secondary glioblastomas and their lower-grade precursors are associated with driver mutations of (2)
IDH1 and IDH2
T/F most primary glioblastomas are IDH–mutant, WHO grade IV
False, most primary glioblastomas are IDH–wild type, WHO grade IV
Diffuse Astrocytoma vs Anaplastic
more densely cellular, more notable nuclear atypia and presence of mitosis
Anaplastic astrocytoma vs Glioblastoma
features of anaplastic + necrosis and hypervascularity
Mutations in primary glioblastoma (4)
TERT, EGFR, CDKN2A, TP53
Primary vs secondary glioblastoma
Primary - older, no precursor lesion, IDH-wild type, TERT mutations
Secondary - younger, with precursor astrocytoma, IDH mutant, ATRX mutant
Oligodendroglioma is molecularly defined by IDH ____ and codeletion of
mutant, and codeletion of 1p and 19q
brain tumor composed of sheets of regular cells with spherical nuclei containing finely granular chromatin surrounded by a clear halo of vacuolated cytoplasm and typically contains a delicate network of anastomosing capillaries, resembling “chicken wire.”
Oligodendroglioma
distinct genetic alteration in Pilocytic astrocytoma (WHO grade 1)
KIAA1549-BRAF gene fusion/ duplication
brain tumor with a biphasic architecture combining loose “microcystic” and compact, densely fibrillar areas.
Pilocytic astrocytoma
T/F presence of microvascular proliferation or necrosis in Pilocytic astrocytoma implies an unfavorable prognosis
False
Characteristic finding in Pilocytic astrocytoma (4)
biphasic, limited brain invasion, hair-like processes, rosenthal fibers
tumors that most often arise in proximity to the ependyma-lined ventricular system, including the oft-obliterated central canal of the spinal cord.
Ependymoma
commonly mutated in ependymomas arising in the spinal cord
NF2 gene
distinct lesions that occur in the filum terminale of the spinal cord. Cuboidal tumor cells are arranged in a variably papillary architecture around mucin-rich fibrovascular cores.
Myxopapillary ependymomas (WHO grade I)
tumors composed of a mixture of mature neuronal and glial cells. They are typically superficial lesions that present with seizures and are the most common neuronal tumors in the CNS
Gangliogliomas (WHO grade I)
Approximately 20% to 50% of gangliogliomas have an activating mutation in
BRAF V600E
most common brain embryonal neoplasm which occurs predominantly in children and exclusively in the cerebellum
medulloblastoma
Molecular subtypes of medulloblastoma reveal alterations of signaling pathways (2)
sonic hedgehog–patched (SHH) pathway and WNT/β-catenin signaling pathway
characteristic finding in classic subtype of medulloblastoma
Homer Wright rosettes
most common CNS neoplasm in immunosuppressed individuals, including those with AIDS and immunosuppression after transplantation
Primary CNS lymphoma
Primary CNS lymphoma in the setting of immunosuppression, the malignant B cells are usually latently infected by
EBV