Case Number : Case 1700 - 2 December - Dr Richard A Carr Posted By: Guest

Richard has got a special case for you today to mark our 1700th Spot Diagnosis Case... enjoy

Cheers, Geoff Cross - DermpathPRO Projects

Lymphangiosarcoma with prolonged- standing lymphedema, could be Stewart-Treves syndrome.

Although morphology (and history) is highly suggestive of angiosarc, I think CD31 is negative (background staining), not that typical of angiosarc. On the contrary, CD45 is positive. So I think this is a Lymphoma (T cell anaplastic lymphoma, small cell variant) mimicking angiosarc. Waiting for more lymphoproliferative markers to be presented!

Lymphangiosarcoma is my second diagnosis, because neoplastic cell population is strongly resembling "plasma cells".

CD138?

My first spot diagnosis is extramedullary plasmacytoma.

Challenging case. As some of the colleagues remarked I thought CD45 is partially expressed and the cells are extremely discohesive so lymphoma must be the first thought. I would perform a first panel of CD20 (or PAX-5), CD3, CD15, CD30. I did not think the cells have a plasmacytoid morphology but who knows...

resembling plasma cells as neoplastic and malignant plasma cells ( plasma blasts )... sorry for my approximate word! But I think it's important, as Mona and Raul remarked, to perform a lymphoma-panel...a leg type of DLBCLy can happen in chronic lymphedema, for example... 

besides lymphoma, would also think of retiform hemangioendothelioma in this case. CD 31 is equivocal, perhaps repeating it, and a factor VIII, D2-40 along with lymphoma panel

after viewing images again, I would strongly favour retiform haemangioendothelioma

I believe this is a case of angiosarcoma. CD31 is equivocal indeed. I would perform other immunostains like FLI-1 and Ki-67.

Difficult case with a range of differentials! Just to throw another one in, my first thought was an unusually florid pseud-Kaposi's (acroangiodermatitis). The negative CD34 and CD31 would be in keeping. However, the cells are rather atypical looking and plump (and not bland spindle shaped as would be expected in pseudo-Kaposi's). So, agree with colleagues that we need a broader immuno panel to definitely rule out a lymphoma or angiosarcoma. 

Thought of lymphoma (Cutaneous ALCL) mimicking Stewart-Treves angiosarcoma.

http://www.ncbi.nlm.nih.gov/pubmed/7894104

I find ERG to be and extremely useful marker for vascular tumors (in combination with CD31). However I have never seen an angiosarcoma not expressing both cd31 and cd34. Look at this article by Dr. Miettinen in the section of angiosarcomas 88/89 positive with cd31. I imagine double negatives can happen (once in a lifetime) but I would rule out lymphoma first

It’s hard not to think of angiosarcoma based on case history and HE images, but I’m slightly confused after IHC images. Maybe we will have new and elucidative IHC images.

At first glance, i thought of angiosarcoma but as other colleages spotted, vascular markers are negative in discohesive round atypical cells. so ,i think lymphoma or maybe other small round cell neoplasms should further be ruled out with extended IHC panel.

With the history provided, the clinical setting looks apt for pseudo-Kaposi's. Plenty of hemosiderin present. However, the atypia does bother me. Papillary intralymphatic angioendothelioma (PILA)? There are lymphoid cells that can be present in the latter. The growth pattern does not seem that of a conventional lymphoma, unless it is some intravascular type.

This was a very tricky case due to the immunostains!  Clinically it was a barn-door looking angiosarcoma and H&E compatible with angiosarcoma too. I too was confused by the negative CD31 & CD34 however all other markers in the small blue cell group of differential diagnoses were also negative or unhelpful (DDx included PNET, synovial sarcoma, MPNST, melanoma, neuroendocrine  carcinoma, lymphoma, rhabdomyosarcoma etc). The case was kindly reviewed by regional soft tissue colleagues who repeated the CD31 & CD34 reporting focal staining and ERG was also reported to be positive.  I'm not sure we considered plasma cell tumour - good thought and I'll pass the message on.

Final conclusion: Angiosarcoma (with small blue cell differentials).