Rosettes are little round groupings of cells found in tumors. They usually consist of cells in a spoke-wheel or halo arrangement surrounding a central, acellular region. Rosettes are so named for their resemblance to the rose windows found in gothic cathedrals (check out the beautiful rose window in the Cathedral of Notre-Dame in Strasbourg).
There are a bunch of different kinds of rosettes, each with different types of cells and different names. Most of them are found in tumors of the nervous system. It’s useful to be able to recognize these, because they help with the diagnoses of difficult tumors. Plus, somebody will definitely ask you about them on some pathology exam somewhere.
Let’s take a look at the four main kinds of rosettes. You’ll want to remember what each type of rosette looks like, what’s in the lumen (if anything), and which tumors it is found in.
Homer Wright rosette
This rosette, named for James Homer Wright, the first director of the Massachusetts General Hospital, is typically seen in neuroblastomas, medulloblastomas, and primitive neuroectodermal tumors (PNETs). It consists of a halo of tumor cells surrounding a central region containing neuropil (hence its association with tumors of neuronal origin).
This rosette (named for pathologist Simon Flexner and ophthalmologist Hugo Wintersteiner) is characteristic of retinoblastomas. It consists of tumor cells surrounding a central lumen that contains cytoplasmic extensions from the tumor cells. If you look at the tumor cells under electron microscopy, they have features of primitive photoreceptor cells.
True Ependymal Rosette
This rosette (seen in – you guessed it – ependymoma) consists of tumor cells surrounding an empty lumen. It is thought that these structures represent attempts by the tumor cells to recreate little ventricles with ependymal lining. One thing to note: although these guys are characteristic of ependymoma, they’re not seen in every case. In fact, it’s fairly uncommon to find them at all (they’re only present in a small percentage of well-differentiated ependymoma).
This rosette consists of tumor cells collected around a blood vessel. It’s called a pseudorosette because the central structure isn’t part of the tumor. In the past, the term pseudorosette meant any rosette that didn’t have a truly empty lumen…but it seems that designation is kind of outdated. These rosettes are common in ependymomas, but you also see them in medulloblastoma, PNET, central neurocytomas, and glioblastomas.
Nice Keep it UP
Cool. Never heard of this one actually. Learn something new everyday!
Thanks, Kevin! Glad you found something new.
Dear doctor: This article is good! i have a little question about rosette: in nephroblastoma (Wilms tumor) we also see some “rosette” (somebody will call it rosette-“like”..i don’t know which is right), what kind of rosette should it be? Thanks!! Really like this blog!
The circular structures in Wilms tumor are perhaps better called “epithelial tubules.” They consist of tall columnar epithelial cells surrounding an empty lumen. Sometimes, these tubules can appear similar to the rosettes seen in neuroblastoma. However, in neuroblastoma, the rosettes do not contain a true lumen. Here is an image of a tubular structure in Wilms tumor: http://www.pathpedia.com/Education/eAtlas/Histopathology/kidney/wilms_tumor_(nephroblastoma).aspx.
Got to know something in much better way, all rosettes in one page!! Thanx doctor..
great … Thank u
good delivery. tanx
Thanks a lot vv helpful, keep up the good work!
simple and really informative…
simply concise and concept clearing
Thank doctor! It’s really usefull, love it!
good and valuable information, thnx doc
it is so useful.I undrestood Flexner-Wintersteiner Rosette well
Thank you. It was very helpful.
thank u so much for the information.it is really important from viva point of view.
also refer http://www.ajnr.org/content/27/3/488.full.pdf+html for further information on rosette and pseudorosettes.
Described in a very simplified way
Thanks doctor..very useful information..
This heterogenous collection of histological features & terms has been bugging me for a year! Thanks for finally helping me clear this up and keep it all straight.
Thank you so much. Made my day. Always confused when it comes to “rosettes”. Even made a mistake in my PG entrance. 🙁 Guess it won’t happen again. 🙂
I really like all your pages. Keep up the good work doc.
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It’s interesting how this terminology relates to veterinary pathology. All these types are also seen, but perhaps related to other diagnoses. For example in canine or feline ependymoma, there are all: Flexner- Wintersteiner, Homer Wright and pseudo rosettes, but no “true ependymoma rosettes” mentioned above. I wonder if with time some of this terminology borrowed from human pathology but now commonly used in veterinary pathology actually got another meaning or got to denotes something at least a bit visually different.
I would appreciate somebodies takes (views) on that.