Case Number : Case 2464 - 12 December 2019 Posted By: Saleem Taibjee

Dermal nodular fasciitis?

Agree with Mona, I would take into account BFH vs. Leiomyoma, as well.

17 hours ago, Dr. Mona Abdel-Halim said:

Dermal nodular fasciitis?

 

Yes! Dermal NF, polypoid variant

spindle cell  juvenile xanthogranuloma to be also considered. I am not able to see giant cells

Agree with dermal nodular fasciitis.

Nodular fasciitis was considered in the differential diagnosis, but in the end was not favoured. The silhouette is the clue.

OK! The silhouette would be typical of epithelioid histiocytoma... but, sailing like a salmon, against the current, I favor a polypoid nodular fasciitis ( Bracey TS, Wharton S, Smith ME.J Cutan Pathol. 2009 Sep;36(9):980-2. doi: 10.1111/j.1600-0560.2008.01159.x.).

There are some large cells with vesicular nucleus, prominent nucleolus, and abundant basophilic cytoplasm, reminiscent of ganglion cells. I agree with everybody that the lesion looks like nodular fasciitis, but since we see ganglion-like cells, the correct term is probably something starting with "proliferative" such as proliferative fasciitis or myositis, But those lesions are usually deep located. I checked Pubmed and there are rare cases of intradermal proliferative fasciitis which I think this case might represent an example of that entity. Don't know whether the lesion would have a fusion gene involving USP6 or not?

Thank you for the interesting discussion on this case, which is probably not clear-cut. I agree that there are nodular fasciitis like features, and am interesting to learn about the polypoid variant described. However, the ALK was convincingly positive in this case (see below), and many of you will be aware of the relatively recent literature regarding ALK fusions (with concomitant ALK expression on immuno) now identified in epithelioid fibrous histiocytoma e.g. https://www.ncbi.nlm.nih.gov/pubmed/25413595. Admittedly this is not an entirely specific finding, but as far as I am aware, has not been shown in nodular fasciitis (please correct me if I am wrong). I did share the case with Eduardo Calonje, and his opinion was also of EFH. He tells me he has seen other instances of this rather 'spindle cell variant' of EFH which often causes confusion. I also shared the case with Raul Perrett. His comments as follows: "Yes Saleem it did cross my mind and after reviewing the case I think you are right. I have never seen an EFH with a predominant spindle cell component very closely resembling myofibroblasts + myxoid areas. However, this has been already published! (https://www-ncbi-nlm-nih-gov.gate2.inist.fr/pubmed/29430713). Considering the genomic and morphological features of EFH, I think it is probably more closely related to myofibroblastic tumors than fibrous histiocytoma/dermatofibroma."

This was my own patient. The clinical appearance was of an exophytic polypoid red lesion which certainly (in hindsight) could have been EFH rather than my clinically favoured pyogenic granuloma. Sadly I did not take a photograph before shaving the lesion!

Amazing case Saleem! It seems the advances in molecular biology will change all our norms and standards! Thank u for sharing. 

Learned a lot today...Thanks, Dr Saleem!

Thank u so much Dr Saleem. I thought of EFH but this is the first time to see its spindle cell form. 

Other cutaneous neoplasms that could be Alk-positive and I would consider in this case would be Spitz nevus (my first hypothesis) and Angiomatoid fibrous hystiocytoma (more related to soft tissue and has different histology findings). Was Spitz nevus ruled out? Nice case.

Thanks, Igor. Melanocytic markers (S100, Melan-A) were negative.

Thanks, Saleem!

sir, inflammatory myofibroblastic tumour is all positve

However morphology is different

alk positive