View source for Flexner-Wintersteiner rosette

[[Image:Retinoblastoma rosette.jpg|thumb|'''Flexner-Wintersteiner rosettes''' in [[Retinoblastoma]].]]
'''Flexner-Wintersteiner rosette''' is a spoke and wheel shaped [[cell (biology)|cell]] formation seen in [[retinoblastoma]] and certain other [[Ophthalmology|ophthalmic]] [[tumor]]s.<ref name="thefreedictionary.com">[http://medical-dictionary.thefreedictionary.com/Flexner-Wintersteiner+rosette Definition of 'rosette'], from The Free Dictionary. Retrieved 6 January, 2010.</ref> 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]].<ref name="thefreedictionary.com"/>

==History==
Flexner-Wintersteiner rosettes were first described by [[Simon Flexner]] (1863–1946), a [[physician]], [[scientist]], [[Academic administration|administrator]], and [[professor]] of experimental [[pathology]] at the [[University of Pennsylvania]] (1899–1903). Flexner noted characteristic clusters of cells in an infantile [[Ocular oncology|eye tumor]] which he called retinoepithelioma.<ref>Flexner S. A peculiar glioma (neuroepithelioma?) of the retina. Johns Hopkins Hosp Bull 1891;2:115–19</ref><ref>Schatski SC. Simon Flexner. AJR Am J Roentgenol 1997;169:1395–96.</ref><ref>Bendiner E. Simon Flexner: his "rock" was for the ages. Hosp Pract 1988;23:213–66</ref> A few years later, in 1897, [[Austrians|Austrian]] [[ophthalmologist]] [[Hugo Wintersteiner]] (1865–1946) confirmed Flexner’s observations and noted that the cell clusters resembled rods and cones.<ref>Wintersteiner H. Die zellen der geschwulst. In: Das neuroepithelioma retinae: Eine anatomische und klinishe studie. Leipzig: Franz Deuticke; 1897:12–16</ref> These characteristic rosette formations were subsequently recognized as important features of retinoblastomas.

==Characteristics==
The tumor cells that form the Flexner-Wintersteiner rosette surround a central lumen containing small cytoplasmic extensions of the encircling cells. Unlike the center of the [[Homer Wright rosette]], the central lumen is devoid of fiber-rich neuropil. Like the Homer Wright rosette, the Flexner-Wintersteiner rosette represents a specific form of tumor differentiation.<ref name="McLean">McLean IW, Burnier MN, Zimmerman LE, et al. Tumors of the retina. In: Atlas of tumor pathology: tumors of the eye and ocular adnexa. Washington, DC: Armed Forces Institute of Pathology; 1994:97–154</ref><ref>Donoso LA, Shields CL, Lee EY-H. Immunohistochemistry of retinoblastoma. Ophthal Paediatr Genet 1989;10:3–32</ref><ref>Vrabec T, Arbizo V, Adamus G, et al. Rod cell-specific antigens in retinoblastoma. Arch Ophthalmol 1989;107:1061–63</ref><ref>Kivela T. Glycoconjugates in retinoblastoma: a lectin histochemical study of ten formalin-fixed and paraffin embedded tumours. Virchows Arch A 1987;410:471–79</ref> [[Electron microscopy]] reveals that the tumor cells forming the Flexner-Wintersteiner rosette have ultrastructural features of primitive photoreceptor cells.<ref>Ts’o MOM, Fine BS, Zimmerman LE. The Flexner-Wintersteiner rosettes in retinoblastoma. Arch Pathol 1969;88:664–71</ref> Furthermore, the rosette lumen shows similar staining patterns as in rods and cones,<ref>Zimmerman LE. Retinoblastoma and retinocytoma. In: Spencer WH, ed. Ophthalmic pathology: an atlas and textbook. Philadelphia: WB Saunders; 1985:1292–351</ref> suggesting that Flexner-Wintersteiner rosettes represent a specific form of retinal differentiation. In addition to being a characteristic finding in retinoblastomas, Flexner-Wintersteiner rosettes may also be found in [[pinealoblastoma]]s and [[medulloepithelioma]]s.<ref name="McLean"/>

==References==
{{reflist}}
{{Medical-stub}}

[[Category:Ophthalmology]]
[[Category:Pathology]]
[[Category:Oncology]]
[[Category:2Fix]]