Abstract
Background: Cutaneous mastocytosis is a rare group of disorders characterized by a pathologic accumulation of mast cells in the skin. The most common presentation of cutaneous mastocytosis in adults is maculopapular cutaneous mastocytosis/urticaria pigmentosa, which includes urticaria pigmentosa and telangiectasia macularis eruptive perstans. Currently, there are no definitive diagnostic cut-offs for number of mast cells per 5 high power fields (or per 1 mm2) to meet criteria for cutaneous mastocytosis.
Methods: We identified adult patients diagnosed with cutaneous mastocytosis on skin biopsy as well as age-match controls from normal skin from routine procedures. All slides were stained with CD117 and mast cells were counted per 1 mm2 using digital microscopy.
Results: The mean number of mast cells per 1 mm2 in the mastocytosis cases was 209.1, and the mean number of mast cells per 1 mm2 in the control group was 53.0. Cut-point analysis of our data indicated an optimal cutpoint of 76 mast cells.
Conclusion: This study provides preliminary data that 76 mast cell per 1 mm2 may represent a cutoff value for diagnosing adult patients with cutaneous mastocytosis. Future studies should include larger sample size and comparison to other inflammatory conditions.
