Case Number : Case 2474 - 27 December 2019 Posted By: Dr. Richard Carr

Dermatomyofibroma? SMA and Muscle specific actin? CD34?

epidermal reaction with a green zone and somewhat spindle cell tumor is seen

No invading the sub cutaneous fat

I agree with dermatomyofibroma

I saw very thick elastic fibers with fragmented some. ? Verheoff van Gieson stain.So I would like to add elastofibroma.

Desmin positivity will make it leiomyoma not dermatomyofibroma  (I think this is the plaque variant of leiomyoma from the clinical description). I was not aware with Fumarate IHC (Fumarate hydratase) in leiomyomas so I had to read about it. It appeared that its loss in cutaneous leiomyomas is a sensitive and specific marker for detection of Hereditary Leiomyomatosis and Associated Renal Cell Carcinoma with an overall sensitivity and specificity of 70% and 97% respectively according to this article: 

https://journals.lww.com/ajsp/pages/articleviewer.aspx?year=2017&issue=06000&article=00010&type=Abstract

great learning case Dr

Thanks Mona that was the reference I wanted to highlight.

In this case Raul Perret kindly reviewed the case and undertook the staining.

My differential included plaque like leiomyoma and a smooth muscle hamartoma / Becker's. Clinically is was not suggestive of a Becker. She did have a history of fibroids so we wanted to r/o Reed's syndrome. Raul states: Fumarate expression was conserved (see attached image). Based on this phenotype, the possibility of Reed sybdrome is low.