Case Number : CT0074 Adam_Bates

urticaria pigmentosa
 

Mastocytosis (urticaria pigmentosa. Beautiful pictures!
 

This is langerhans cell histiocytosis for CD1a, S100 and Langerin
 

A lot of mast cells with sparse eos , Urticaria Pigmentosa
 

I think yes it is Langerhans cell histiocytosis, some cells have reniform nuclei..
 

Urticaria Pigmentosa. (not the right milieu of cells for LCH)
 

I think this is LCH with some cells showing a suggestion of longitudinal nuclear grooves. Confirm with immunos: CD1a, S100 protein and MCT.
 

Difficult case, hence the split in diagnoses. The correct diagnosis is urticaria pigmentosa. The lack of pagetoid spread would be against LCH. However special stains would confirm the correct diagnosis if there were any doubt.