title: Perivascular mast cells in urticaria pigmentosa.
abstract: We have quantified perivascular mast cells in cases of urticaria pigmentosa, urticaria, and dermal hypersensitivity reactions. To facilitate reproducibility, the mast cells were counted for a precisely defined vessel unit. These vessel units were divided arbitrarily into those < or = 55 microns and > 55 microns in largest diameters. Urticaria pigmentosa showed an average of 6.4 +/- 1.9 and 22.8 +/- 13.2 mast cells for vessel unit < or = 55 microns and > 55 microns, respectively. Urticaria yielded a lower number of mast cells: 1.5 +/- 0.2 and 2.9 +/- 0.9 for the same respective vessel units. Dermal hypersensitivity reactions revealed an average of 1.6 +/- 0.4 and 2.2 +/- 0.7 mast cells, and the normal skin showed 1.5 +/- 0.3 and 2.4 +/- 0.6 mast cells for each of the vessel units of < or = 55 microns and > 55 microns. The perivascular mast cell distributions of urticaria pigmentosa are statistically different from those of urticaria and dermal hypersensitivity reactions with p < 0.0001. No statistical difference was noted between urticaria, dermal hypersensitivity reactions, and normal skin. The percentages of vessel units < or = 55 microns with > or = 5 mast cells and vessel units > 55 microns with > or = 10 mast cells were determined for each case. The average percentage of vessel units for the former and latter in urticaria pigmentosa was 82.6% and 58.9%, respectively. Urticaria yielded 0% and 0.2%, respectively. None of vessel units in the dermal hypersensitivity reactions or normal skin contained more than 5 mast cells in vessel units < or = 55 microns and more than 10 mast cells in vessel units > 55 microns. Cases of urticaria pigmentosa can be distinguished from other cutaneous eruptions containing mast cells using a simple counting technique on Giemsa stained sections.
authors.affiliation: Departments of Pathology, Stanford University Medical Center, CA 94305, USA.
authors.forename: W L
authors.initials: WL
authors.lastname: Sweet
authors.forename: B R
authors.initials: BR
authors.lastname: Smoller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008407:Mast Cells / Q000473:pathology*; D008875:Middle Aged; D012867:Skin / Q000098:blood supply* / Q000473:pathology*; D014582:Urticaria Pigmentosa / Q000473:pathology*