.png)
Marks dermal dendrocytes and is used for histiocytic phenotyping. Factor XIIIa also stains capillary hemangiomas and certain central nervous system tumors. In combination with CD34, it helps differentiate dermatofibroma (Factor XIIIa positive) from dermatofibrosarcoma protuberans (CD34 positive).
Tissue Block: Formalin-fixed, paraffin-embedded (FFPE) tumor block preferred.
Unstained Slides: Recommended 2 charged slides per stain requested (minimum of 1 slide per stain), baked or unbaked.
Fixation: Tissue must be fixed in 10% neutral buffered formalin for 6–72 hours.
Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.