Intestinal mucosal mast cells: enumeration in urticaria pigmentosa and systemic mastocytosis

Endoscopic gastrointestinal mucosal biopsy specimens from one patient with systemic mastocytosis and five with urticaria pigmentosa (UP) were fixed with Carnoy's reagent and then stained for chloracetate esterase. The mast cell population densities were enumerated in the mucosa using cursor planimetry. Compared with controls, mast cell counts were increased in gastric and duodenal but not sigmoid mucosae. On a histological basis, systemic involvement would appear commoner in urticaria pigmentosa than is generally expected. Gastrointestinal symptoms did not relate to elevated mucosal mast cell counts.