Myeloid Sarcoma : CD61

Comments:
Immunohistochemistry of Myeloid Sarcomas: The most common positive markers in paraffin sections include: CD68/KP1, MPO, CD117, CD99, lysozyme, CD34, TdT, CD43, CD56, CD61, CD163 (monocyte-specific), glycophorin and CD4.

Rare cases show aberrant expression of CD30 or cytokeratin.

T- and B-cell markers such as CD3, CD5, and CD20 are usually negative, although aberrant expression may be seen.

This image shows CD61 immunoreactivity in a case of megakaryoblastic myeloid sarcoma involving small bowel. Presence of megakaryocyte-restricted antigens like CD41 and CD61 by flow cytometry or immunohistochemistry supports megakaryocytic lineage (such as in acute megakaryoblastic leukemia or megakaryoblastic myeloid sarcoma).

Image courtesy of: The New York Pathological Society (@NYPathSociety); used with permission.