Palisade (pathology)

Flexner-Wintersteiner rosetteHomer Wright rosetteHomer Wright rosettespalisadingFlexner-Wintersteiner rosettesFlexner–Wintersteiner rosetteHomer Wright (HW) rosettesHomer Wright pseudorosettespalisadedPseudorosette
In histopathology, a palisade is a single layer of relatively long cells, arranged loosely perpendicular to a surface and parallel to each other.wikipedia
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Retinoblastoma

retinal cancerbilateral retinoblastomaeye cancer
Flexner–Wintersteiner rosettes (spoke-and-wheel shaped cell formation seen mainly in retinoblastoma ) have been described as a form of palisading. A Flexner–Wintersteiner rosette is a spoke-and-wheel shaped cell formation seen in retinoblastoma and certain other ophthalmic tumors.
Undifferentiated elements appear as collections of small, round cells with hyperchromatic nuclei; differentiated elements include Flexner-Wintersteiner rosettes, Homer Wright rosettes, and fleurettes from photoreceptor differentiation.

Simon Flexner

Flexner–Wintersteiner rosettes were first described by Simon Flexner (1863–1946), a physician, scientist, administrator, and professor of experimental pathology at the University of Pennsylvania (1899–1903).
In addition, Flexner was the first to describe Flexner-Wintersteiner rosettes, a characteristic finding in retinoblastoma, a type of cancer.

Medulloepithelioma

In addition to being a characteristic finding in retinoblastomas, Flexner–Wintersteiner rosettes may also be found in pinealoblastomas and medulloepitheliomas.
Flexner-Wintersteiner rosettes may also be observed.

Medulloblastoma

medulloblastomascancer of the brain and spine
Examples of tumors containing these are neuroblastoma, medulloblastoma, pinealoblastoma, and primitive neuroectodermal tumors of bone.
Both perivascular pseudorosette and Homer Wright rosette pseudorosette formation are highly characteristic of medulloblastomas, and are seen in up to half of cases.

Neuroblastoma

Neuroepitheliomaa rare form of cancerCNS Neuroblastoma
Examples of tumors containing these are neuroblastoma, medulloblastoma, pinealoblastoma, and primitive neuroectodermal tumors of bone.
On microscopy, the tumor cells are typically described as small, round and blue, and rosette patterns (Homer Wright pseudorosettes) may be seen.

Ameloblastoma

Peripheral ameloblastoma
Palisades that are generally longer than a rosette or pseudorosette can be seen in neural tumors such as Schwannoma, as well as in ameloblastomas.
The most common follicular type has an outer arrangement of columnar or palisaded ameloblasts-like cells and inner zone of triangular shaped cells resembling stellate reticulum from the bell stage of tooth development.

Basal-cell carcinoma

basal cell carcinomabasal cell cancerrodent ulcer
It can also be seen in nodular basal-cell carcinomas.
Histopathology shows aggregates of basaloid cells with well-defined borders, showing a peripheral palisading of cells and one or more typical clefts.

James Homer Wright

James WrightWright
They are named for James Homer Wright.
He is the "Wright" in Wright's stain, and the "Homer Wright rosettes" associated with neuroblastoma.

Histopathology

histopathologicalhistopathologichistopathologist
In histopathology, a palisade is a single layer of relatively long cells, arranged loosely perpendicular to a surface and parallel to each other.

Cell (biology)

cellcellscellular
Flexner–Wintersteiner rosettes (spoke-and-wheel shaped cell formation seen mainly in retinoblastoma ) have been described as a form of palisading.

Neoplasm

tumortumorstumour
A Flexner–Wintersteiner rosette is a spoke-and-wheel shaped cell formation seen in retinoblastoma and certain other ophthalmic tumors.

Granulocyte

granulocytesgranulocytopeniapolymorphonuclear leukocyte
A rosette is a structure or formation resembling a rose, such as the clusters of polymorphonuclear leukocytes around a globule of lipid nuclear material, as observed in the test for disseminated lupus erythematosus.

Lupus erythematosus

lupussystemic lupus erythematosusCutaneous lupus erythematosus
A rosette is a structure or formation resembling a rose, such as the clusters of polymorphonuclear leukocytes around a globule of lipid nuclear material, as observed in the test for disseminated lupus erythematosus.

Electron microscope

electron microscopyelectron microscopeselectron
Electron microscopy reveals that the tumor cells forming the Flexner–Wintersteiner rosette have ultrastructural features of primitive photoreceptor cells.

Pinealoblastoma

pineoblastoma
In addition to being a characteristic finding in retinoblastomas, Flexner–Wintersteiner rosettes may also be found in pinealoblastomas and medulloepitheliomas. Examples of tumors containing these are neuroblastoma, medulloblastoma, pinealoblastoma, and primitive neuroectodermal tumors of bone.

Pathology

pathologistpathologicalpathologies
Flexner–Wintersteiner rosettes were first described by Simon Flexner (1863–1946), a physician, scientist, administrator, and professor of experimental pathology at the University of Pennsylvania (1899–1903).

University of Pennsylvania

PennThe University of PennsylvaniaPennsylvania
Flexner–Wintersteiner rosettes were first described by Simon Flexner (1863–1946), a physician, scientist, administrator, and professor of experimental pathology at the University of Pennsylvania (1899–1903).

Eye neoplasm

eye cancerocular oncologyocular cancer
Flexner noted characteristic clusters of cells in an infantile eye tumor which he called retinoepithelioma.

Austrians

AustrianAustriaAustrian Germans
A few years later, in 1897, Austrian ophthalmologist Hugo Wintersteiner (1865–1946) confirmed Flexner’s observations and noted that the cell clusters resembled rods and cones.

Ophthalmology

ophthalmologistophthalmicoculist
A Flexner–Wintersteiner rosette is a spoke-and-wheel shaped cell formation seen in retinoblastoma and certain other ophthalmic tumors. A few years later, in 1897, Austrian ophthalmologist Hugo Wintersteiner (1865–1946) confirmed Flexner’s observations and noted that the cell clusters resembled rods and cones.

Neuropil

neuropil threadsneuropilslobula plate
A Homer Wright pseudorosette is a type of pseudorosette in which differentiated tumor cells surround the neuropil.

Primitive neuroectodermal tumor

ependymoblastomaPNETCNS Primitive neuroectodermal tumour
Examples of tumors containing these are neuroblastoma, medulloblastoma, pinealoblastoma, and primitive neuroectodermal tumors of bone.

Schwannoma

schwannomasneurilemmomaNeurinoma
Palisades that are generally longer than a rosette or pseudorosette can be seen in neural tumors such as Schwannoma, as well as in ameloblastomas.

Necrosis

necroticnecrotizingnecrotic tissue
Pseudopalisading, a visually similar finding, is the formation of hypercellular zones that typically surrounds necrotic tissue.