In the immunohistochemical analysis, the cells exhibited diffuse membranous positive staining with CD99
and vimentin, while cytokeratin was negative (Fig.
Epithelial membrane antigen (EMA) and CD99
stains were negative.
Immunohistochemistry revealed positive staining of the tumor cells for CD43 and myeloperoxidase (negative for CD20, CD79a, CD30, CD99
, CD3, CD138, AE1/3 and Cam 5.
Expression of CD99
is shared by subsets of myeloid sarcoma and pediatric small blue cell tumors, perhaps contributing to confusion.
There was no staining for AE1 AE3, pancytokeratin, H-caldesmon, myogenin, CK 5/6, CK14, p63, 34BE12, CD34, CK7, CD56, EMA, S100, melan A, c-KIT and CD99
The findings were of a "small round blue cell" tumour showing mesenchymal differentiation and immunohistochemical positivity for CD99
, vimentin, Bcl-2, focal positivity for NSE together with glycogen found within the cytoplasm.
In immunochemistry, CK20 was strongly positive, SI00 was focally positive, and EMA was positive, while synaptophysin, chromogranin, vimentin, CD3, CD20, as well as CD45, and CD99
were all negative.
Hastadan alinan metastatik nodulun histopatolojik incelemesi; CD99
negatif, 6c1-2 pozitif monofazik synovial sarkom olarak geldi.
showed weak cytoplasmic staining, which is consistent with a primitive neural or neuroectodermal-type neoplasm.
Neoplastic cells were strongly positive for CD20 and negative for cytokeratin, desmin, CD79a, S100, and CD99
The mass stained positive for CD99
and Bcl2, weakly positive for CD34 and smooth muscle actin, and negative for CD31 and EMA.
Positive immunostaining for Bcl-2 and CD99
is also observed in solitary fibrous tumors, but their presence is not uniform and positivity is often weak.