Case Number : Case 1428- 14 December Posted By: Guest

I think this is some kind of morfologyc variant of intradermal melanocytic nevus with pseudo-physalipherous cells. In a younger patient my first hypothesis would be intradermal Spitz nevus.

Me I was thinking more of a neuroid variant of fibrous papule. I agree that the nuclei and architecture of cells makes think of nevus. Would consider doing s100, factor XIIIa and cd34 

Yeah but I checked that article cited in Weedons and it just looks like a regular clear cell fibrous papule.

Fibrous papule of the face, clear cell type: a case report.

Would favour a fibrous papule. Would do S-100 to rule out a naevus variant, and a cytokeratin.

Agree with Raul and Mona: clear cell variant of fibrous papule of the nose.

Agree with fibrous papule with clear cells.  I think Dr Hurt posted a similar case a few months ago. 

What about cellular neurothekeoma?

Cellular neurothekeoma

One can never see too many fibrous papules, which was my diagnosis in this case.  Below are the specifics from my report:

SKIN, LEFT NASAL SIDEWALL , SHAVE BIOPSY :

-- FIBROUS PAPULE

COMMENT:  I think this is an unusual fibrous papule.  It reminded me to some degree of melanocytes or some type of neural-like cells.  I even considered the possibility of cellular neurothekeoma and chordoma.  Another possibility for consideration was PEComa.  In essence, however, all of these conditions in the differential are excluded because of one reason or another, mostly from negative staining with the various markers used to attempt to rule them in.  As a rule fibrous papules are strongly positive with Vimentin, CD63 and Factor XIIIa.  Some of them in the literature have been described as having CD34 positivity, but this one does not.  Thus, I think this is a variant on the theme of fibrous papule.

Micro:

This lesion from the left nasal sidewall, is characterized by two epicenters of a sharply circumscribed lesion containing cells that are outlined as 1-2 cellular units in small nests.  There is fibrous tissue between these cells, and the entire unit is somewhat circumscribed.  There is no nuclear pleomorphism.  The cells also fail to show any mitotic figures.  A few of them have nucleoli that are slightly off center but most of the nucleoli are relatively small.  There are some pseudoinclusions in these cells.  Immunohistochemical stains show that the cells are negative with S100 protein, negative with Melan-A, negative with p40, negative with CAM5.2, negative with EMA, negative with actin and desmin, negative with adipophilin, NSE, D240 and CD34.  The lesion is positive strongly with vimentin, CD63, and has dendritic cell positivity with Factor XIIIa.  Ki-67 shows a very low index of less than 1% positive.