Answer to Image of the Month December 2014

Submitted by Poonam and Rajalakshmi T


Mastocytosis/Urticaria pigmentosa

The section shows perivascular collections of mast cells, which are monomorphous cells with polygonal outlines and amphophilic, granular cytoplasm. The cytoplasm is replete with granules, which may be highlighted by stains such as Toluidine blue or Leder's stain. In adults, the lesions present commonly as brownish macules, accompanied by telangiectasia.