Management of poorly controlled indolent systemic mastocytosis using narrowband UVB phototherapy.

The mastocytoses comprise a group of proliferative stem cell disorders defined by the abnormal accumulation of mast cells (MCs) in the skin or other body tissues including the bone marrow, gastrointestinal tract, and liver. Systemic mastocytosis is defined by the presence of one major and one minor criterion or 3 minor criteria delineated by the World Health Organization (WHO). We present the case of a 57-year-old woman with a 10-year history of red-brown pruritic maculopapular lesions on the upper and lower extremities and trunk who was originally diagnosed with cutaneous mastocytosis.