Case Number : Case 873 - 23rd October Posted By: Guest

I'd suggest S100 to highlight desmoplastic melanoma with pleomorphic spindle cells with intranuclear cytoplasmic pseudoinclusions.

Agree. The presence of lymphocytes is a clue to desmoplastic melanoma.

I want to add sclerotic fibroma to the differential.

? angiofibroma / fibrous papule.

I always think about a desmoplastic melanoma when I see fusiform atypical cells with a fibrotic stroma and inflammation, but the clinical impression of verruca, the polypoid configuration and the small number of lymphocytes argues against this diagnosis.

It looks like a polypoid lesion with enlarged and pleomorphic cells, probably a Pleomorphic fibroma.

Pleomorphic fibroma

Agree with Dr Mark, first fibrous papule then pleomorphic fibroma. Did not think melanoma here.

I agree with Dr Juan and dr Mark, but I'd use the term: Fibroepithelial Polyp with degenerative Changes

[font=arial,helvetica,sans-serif]I think pleomorphic fibroma is the correct diagnosis. It fits on clinical impression of a verruca.
I don’t consider desmoplastic melanoma as my first choice because it commonly presents on clinical examination as an indurated plaque and on microscopic examination the neoplastic cells have fibroblast-like appearance with mild to moderate cytological atypia rather than those bizarre spindle cells with large pleomorphic and hyperchromatic nuclei that are displayed on pictures above. Anyway, as melanocytic tumors don´t read dermatopathology books, vimentin and S100 will be helpful.
I didn´t find the vascular pattern characteristic of angiofibroma / fibrous papule, except for rare small ectatic vessels in superficial dermis.[/font]

Pleomorphic fibroma

Agree with Robledo's line of reasoning for pleomorphic fibroma. Those are large cells!

agree, pleomorphic fibroma.
As an aside, I have seen 2 recent cases of desmoplastic naevus with lymphocytic reaction which would usually be a feature for melanoma. Has anyone else had a simialr experience?

My first thought- Pleomorphic fibroma

[quote name='Guest' timestamp='1382556021']
agree, pleomorphic fibroma.
As an aside, I have seen 2 recent cases of desmoplastic naevus with lymphocytic reaction which would usually be a feature for melanoma. Has anyone else had a simialr experience?
[/quote]

Saleem- I have seen a number of cases. As far as I understand, a lymphocytic reaction though should make one search hard for a melanoma, is not specific for it. aka Halo Nevus

I called it pleomorphic fibroma.