Case Number : Case 1894 - 31 Aug - Dr Arti Bakshi Posted By: Guest

Nodular faciitis.

As dermpath1 my spot diagnosis is also nodular fasciitis. Nevertheless, we have to perform a small panel of immunos in cases like this one (CD34, S-100, EMA, SMA) in order to discard common differentials

I agree with my Colleagues, despite my difficulty in distinguishing between myxoid variant of fibromatosis(there are many clear perivascular spaces with vessels standing out in the background) and keloidal/fibromatosis-like variant of nodular fasciitis ( feathery ganglion like myofibroblasts and extravasated red cells win!). 

I think we can discard the mets hypothesis.

I was wrong!!!

We can't discard metastatic melanoma, desmoplastic, fibromatosis-like!!! I analyzed better the fig 4/5.

So welcome a S100 and other immunomarkers.

My first thought also was nodular fasciitis duo to extravasation of erythrocytes and due to the feathery appearance. Nevertheless, given the recent history of spindle cell melanoma, immunomarkers for rule out a metastasis are mandatory.

Agree with colleagues

The final diagnosis is :  FIBROMATOSIS.

The tumour cells showed diffuse nuclear positivity for Beta Catenin. SMA showed patchy positivity. Desmin, S100 and melan A were all negative.

Well done to Vincenzo for considering this diagnosis in his differential!

The foci of RBC extravasation were indeed misleading for a nodular fascitis. The spindle cell melanoma on his nose was morphologically different (more cellular, pleomorphic and mitotically active) as well as showed a different immunoprofile (S100 and melan A positive)

Nice case Arti.