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Brain
Published in Joseph Kovi, Hung Dinh Duong, Frozen Section In Surgical Pathology: An Atlas, 2019
Joseph Kovi, M.D. Hung Dinh Duong
Pure oligodendrocytic glioma is rare. Oligodendrogliomas often contain a mixed cell population of fibrillary or protoplasmic astrocytes, gemistocytes, astroblasts, and spongioblasts.151 In a series of 102 mixed gliomas, 86 were composed of oligodendroglioma and astrocytoma, and 16 of oligodendroglioma and ependymoma.174 A monotonous population of uniform, moderately large cells with centrally located dark nuclei and vacuolated cytoplasm is highly characteristic of oligodendroglioma. Calcification is a prominent feature in “pure” oligodendroglioma and has been found in 61 (60%) of 102 cases of mixed gliomas. Calcium deposits are not a major finding in sections from astrocytoma and glioblastoma.
Nervous System
Published in Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard, Toxicologic Pathology, 2018
Mark T. Butt, Alys Bradley, Robert Sills
This diagnosis is appropriate whenever there is an increase in the number and size of astrocytes, especially when in the proximity of an identified structural alteration in some component of the central portion of the nervous system. Reactive astrocytosis, gemistocytosis (a gemistocyte is a term for an enlarged/reactive astrocyte), and astrogliosis are synonymous terms.
Astrocytoma
Published in Dongyou Liu, Tumors and Cancers, 2017
Diffuse astrocytoma usually occurs in the cerebrum (frontal and temporal lobes), brain stem, spinal cord, optic nerve, optic chiasm, optic pathway, hypothalamus, and thalamus. The tumor tends to distribute evenly throughout the white matter, resulting in a loss of the normal gray-white junction and making the central region ivory white. With a modest blood supply, the tumor appears less vascular than the adjacent brain. Radiographic imaging demonstrates asymmetry and/or enlargement of a region of the brain, along with abnormal density and signal. Histologic examination of unfrozen tissue reveals the increased cellular density, modest nuclear pleomorphism, increased intercellular edema, and occasional bubbly collections of fluid (so-called microcysts). Molecularly, diffuse astrocytoma, IDH mutant, harbors a mutated IDH gene (notably IDH-R132H); diffuse astrocytoma, IDH wild type, possesses an intact IDH gene; and diffuse astrocytoma, NOS, has undetermined IDH gene status. Gemistocytic astrocytoma, IDH mutant, is a variant of diffuse astrocytoma in which gemistocytes make up >20% of tumor cells and an IDH mutation is present [1].
Infant-Type Hemispheric Glioma in a Chinese Girl: A Newly Defined Entity
Published in Fetal and Pediatric Pathology, 2023
Yuan Fang, Yi-zhen Wang, Xia Wei, Shao-mei Li, Lian Chen
The lesion was densely hypercellular (Fig. 2A). The neoplastic astrocytes displayed various degrees of pleomorphism, with round, oval, and spindle shapes, among which the spindle cells emitted elongated bipolar cell protrusions (Fig. 2B). Cytology showed heteromorphic nuclei of different sizes with uneven distribution of chromatin, leading to vacuolar appearance with occasionally small nucleoli and frequent mitoses (approximately 3/mm2). There was multifocal central necrosis with a cell-free zone, and the surrounding tumor cells were clustered and formed psuedopallisades (Fig. 2C). The necrotic areas showed infiltration of a few lymphocytes, plasma cells and neutrophils. Numerous microvascular proliferations highlighted by reticulin staining was observed, from which red blood cells escaped, accompanied by the deposition of scattered hemosiderin particles (Fig. 2D-F). Ganglion cells or gemistocyte-like cells were absent, and there was no xanthomatous changes or calcifications. These were features of HGG, previously considered a glioblastoma.