Solitary mastocytoma occurring at a site of trauma.

We describe a patient with a solitary mastocytoma arising at a site of trauma. The patient was born with the umbilical cord wrapped around her right thigh and subsequently developed a solitary mastocytoma in the exact site and distribution of this injury. The pathogenesis of mast cell proliferation in solitary mastocytoma is not completely understood. Cytokines released after injury, such as stem cell factor, may stimulate the proliferation of mast cells, as well as fibroblasts and melanocytes to form a mastocytoma. Mast cells in a newborn may be more sensitive to stem cell factor in the presence of cytokines released after injury due to an increased density of c-kit receptors. We present our patient and review the literature to support a hypothesis that this condition represents a reactive, and not neoplastic, process.