Systemic mast cell disease

We present a case of systemic mast cell disease because of its unusual lack of significant manifestations in skin or bone. Clinicians and pathologists alike must be aware of this entity and consider it when atypical round cell infiltrates are present in visceral organs. It should be included in a differential diagnosis with Hodgkin's and non-Hodgkin's lymphomas, leukemias, myeloproliferative disorders, and a variety of nonneoplastic diseases. Cytochemical stains and electron microscopy may be diagnostic.