Case Number : Case 1701 - 5 December - Dr Richard A Carr Posted By: Guest

Richard has given us a case for Newbies and Trainees, enjoy.

Geoff Cross - DermpathPRO Projects

?giant cell fibroblastoma

This case is now open to all comers.

my first thought was plexiform neurofibroma..but there are foci of atypia and hypercellularity.

neurofibroma with atypical features?

Agree with Urmila it was my impression too but to be honest I did not find this case easy. You want to perform s-100 , desmin and cd34.

I thought there were areas looking like cellular angiofibroma and superficial angiomyxoma. In the last picture the cells look rather irregular and sort of more immature (when you compare them to the small rounded plump happy looking cells from cellular angiofibroma). I would have liked to see the deeper portions of the sample as well as adnexal entrapment but again my impression was giant cell fibroblastoma as Urmila suggested

Agree Raul, need to see some immunohistochemistry: S100, CD34, Desmin, SMA, EMA. Some probable mast cells in one of the images, made me consider a neural lesion but the cellular areas not look particularly 'neural'. I too thought of a cellular angiofibroma but can't explain the scatted enlarged smudged nuclei. Also considered a lipoblastoma but can't see any convincing lipoblasts.

I am thinking of plexiform neurofibroma with areas showing features of cellular variant with atypical features.

Giant cell fibroblastoma/DFSP

Also favour giant cell fibroblastoma. Have only seen 1 case in 30yrs!

This was not easy but I wanted the newbies and trainees to have a crack at it first. Well done Urmila for spotting the giant cell fibroblastoma and to Vincenzo for adding the dermatofibrosarcoma protuberans (in this case having large areas of the rare and challenging myxoid variant).  This (DFSP/GCF) is a rather classic association - I have seen it presented in meetings and saw another case myself. Childhood and indeed congenital DFSP is well reported.  This was a case I saw in Malawi while reporting the general histopathology case load during my regular visits to Blantyre doing an autopsy study on cerebral malaria (1995 to 1999) funded by the NIH.  The pathology there was very much biased towards immunosuppression related, infections and childhood. I brought this unusual case back to St Thomas' Hospital and Phillip McKee gave me the diagnosis (I was flummoxed having never seen examples). Clearly he'd recognised this case and remembered the association between DFSP and GCF during his work with Chris Fletcher - see references).

References:

1. https://www.ncbi.nlm.nih.gov/pubmed/17721193

2. https://www.ncbi.nlm.nih.gov/pubmed/1939782

3. https://www.ncbi.nlm.nih.gov/pubmed/2172145

4. https://www.ncbi.nlm.nih.gov/pubmed/12502925

5. https://www.ncbi.nlm.nih.gov/pubmed/2069214

6. https://www.ncbi.nlm.nih.gov/pubmed/2804904