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Cutaneous mastocytosis: TMEP. Deba P Sarma, MD Omaha. M 36, back. Essentially normal epidermis and dermis. Spindly and polygonal cells in the papillary dermis represent mast cells, to be confirmed by Giemsa or Toluidine blue stain and CD 117 immunostain.
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Cutaneous mastocytosis: TMEP Deba P Sarma, MD Omaha
M 36, back Essentially normal epidermis and dermis
Spindly and polygonal cells in the papillary dermis represent mast cells, to be confirmed by Giemsa or Toluidine blue stain and CD 117 immunostain
Giemsa stain: Spindle and dendritic dermal cells with granules represent mast cells
CD 117 immunostain reveals numerous brown stained masts cells in the dermis
Comment • Diagnosis: Telangiectasia macularis eruptiva perstans (TMEP) • Cutaneous mastocytosis include solitary mastocytoma, diffuse erythrodermic mastocytosis, paucicellular mastocytosis (telangiectasia macularis eruptiva perstans [TMEP]), and urticaria pigmentosa (UP). • Urticaria pigmentosa is the most common form and is characterized by multiple oval or round red-brown macules, papules, or plaques. • On stroking, a urticaria pigmentosa or mastocytoma lesion becomes pruritic, edematous, and erythematous (the Darier sign), caused by mast cell degranulation. The Darier sign is not positive in patients with TMEP because the lesions are paucicellular. • In TMEP, epidermis is normal. Dermis shows spindled mast cells best identified by Giemsa or Toluidine blue stain showing cytoplasmic granules. Mast cells are positive with CD 117 immunostain.