BPDCN

Lessons From the Friday Unknowns

Histologic examination reveals a skin biopsy involved by a neoplasm composed of intermediate-size cells. The neoplasm has a diffuse pattern of infiltration, replaces the superficial dermis and extends deeply into adipose tissue.

Immunohistochemical studies show that the neoplastic cells are positive for CD4, CD43, CD56, CD123 and TdT (small subset, <10%), and are negative for CD2, CD3, CD5, CD7, CD8, CD15, CD20, CD30, CD34, CD68, CD163, myeloperoxidase and lysozyme.

In summary, these morphologic and immunohistochemical findings support the diagnosis of blastic plasmacytoid dendritic cell neoplasm.

Link to digital slides: https://bit.ly/3ln1Coq | Slides labeled case 4

Link to digital slides of another case: https://bit.ly/3BRFxUE | Slides labeled case 1