Case Number : Case 2248 - 24 January 2019 Posted By: Raul Perret

Epithiliod sarcoma proximal type 

Thinking of some CD20+ or CD30+ Ly. But also S-100- Mart1+ Melanoma.

With the prior history of melanoma i still favor melanoma so we need a SOX10 or MelanA.

If those markers are negatives i would think in some Sarcoma (probably related to treatment for the melanoma)

Epithelioid Sarcoma is a good possibility but also Liposarcoma.

All those markers are negative. INI1 and BRG1 are conserved

Angiosarcoma ( ceruleus cytoplasm! ).

How about CD68 

CD68, Cd34 and ERG negative

Liposarcoma? MDM2 and CDK4?

MDM2 was positive but this is not a liposarcoma

Cytokeratin??

Medullary ca of the breast, anaplastic thyroid ca, anaplastic carcinoma....

I asked for the blocks of the previous lesion to the referring center for comparison. As you see both tumors are morphologically similar/identical, share BRAF expression and interestingly, the previous lesion expressed heterogeneously SOX10 and S100. This process of "dedifferentiation" is rare but has already been described. Good lessons from this case are 1) always checking the morphology of previous tumors in patients with "multiple" neoplasms and 2) Always consider melanoma if morphology is compatible, particularly if  the mass is located deeply in the axillae or groin (frequent metastatic sites). Have a nice day

5 hours ago, Raul Perret said:

I asked for the blocks of the previous lesion to the referring center for comparison. As you see both tumors are morphologically similar/identical, share BRAF expression and interestingly, the previous lesion expressed heterogeneously SOX10 and S100. This process of "dedifferentiation" is rare but has already been described. Good lessons from this case are 1) always checking the morphology of previous tumors in patients with "multiple" neoplasms and 2) Always consider melanoma if morphology is compatible, particularly if  the mass is located deeply in the axillae or groin (frequent metastatic sites). Have a nice day

Thank you Raul! What a fantastic case!

Did you rule out Langerhan's cell sarcoma?

On 05/02/2019 at 09:52, Dr. Richard Carr said:

Did you rule out Langerhan's cell sarcoma?

CD1a negative my friend