Solitary mastocytoma of the eyelid.

Mastocytosis is a heterogeneous group of diseases characterized by the proliferation and abnormal infiltration of mast cells in tissue. These collections of mast cells are called mastocytomas. Solitary mastocytomas are cutaneous lesions, most commonly involving the extremities and trunk. Rubbing a cutaneous mastocytoma lesion leads to the release of histamine and other chemical mediators causing the lesion to become elevated and urticarial, similar to an allergic reaction. We describe a rare location of a presumed solitary mastocytoma of the lower eyelid in a young otherwise healthy child.