Epithelioid sarcoma mimicking granuloma annulare
Wed, 01/07/2009 - 19:43 — Rajni Mandal M.D.
A 49 year old female presented with dermal nodules on her hands.
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A 49 year old female presented with dermal nodules on her hands.
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Comments
Mucin stain in epithelioid sarcoma
It is also essential to know that dermal mucin stains (alcian blue and colloidal iron) will show significant dermal mucin in areas of tumor necrosis is epithelioid sarcoma. This is additional features which may lead a pathologist on the wrong path to misdiagnosis of epithelioid sarcoma as granuloma annulare.
Epitheliod sarcoma
Although granuloma annulare is often included in the dffierentil diagnosis of epithelioid saroma, I do not believe that this approriate. I have seen many examples of each and have yet to confuse one conditon with the other. I believe that is was mentioned a long ago in an atricle or textbook and has been quoted in every puibliation ever since. Careful scruteny of the cellular infiltrate should easily afford their distinction.
Phillip Mcke
confusing epithelioid sarcoma with granuloma annulare
Yet, people do confuse the 2. The presented case is not made up for the sake of discusion. The punch biopsy was initially diagnosed as granuloma annulare and the presented images show how much the 2 conditions can look alike. I put out the above case as unknown several times and in most cases the favored diagnosis was granuloma annulare (even by experience pathologists).
While visiting at Rikshopsitalet in Oslo this August, I was also shown as an unknown a similar case which which was diagnosed as granuloma annulare. I will ask them to share this case to Dermpedia.
So, I think that while entirely agreeing with you that one can distinguish granuloma annulare and epithelioid sarcoma by careful examination of the cellular infiltrate, it is a real and not only academic differential diagnosis.
Artur Zembowicz
Epithelioid sarcoma
In our experience, we have seen at least two cases that had been called granuloma annulare/rheumatoid nodule and after our review we changed the diagnosis to epithelioid sarcoma. Furthermore, if we have any doubts about the diagnosis we definitely consider the possibility of performing an immunohistochemical study for keratin.
Thanks for posting this case!
Victor G. Prieto
I would agree with all
I would agree with all comments made. There may indeed be a striking low power resemblance of GA and epithelioid sarcoma. Furthermore, cytological atypia may be very subtle in areas of epithelioid sarcoma. On larger and more representative specimens however I do not think that one would easily confuse the two entities as there are many clues to a dignosis of epithelioid sarcomas and more classical fields are typically present. The issue arises predominantly on small and superficial biopsies in my opinion. I think your second case is a particularly good mimic but careful examination of the sections shows quite marked atypia beyond that acceptable for GA. Ultimately, I think that both entities can indeed be separated morphologically by Pathologists with significant experience with both entities. Furtunately, immunohistochemistry is helpful in confirming the diagnosis of epithelioid sarcoma but one should remember that multiple antibodies may need to be employed to demonstrate positivity in epithelioid sarcoma.