Histologic examination of the biopsy specimen showed a perivascular and interstitial mast cell infiltrate involving the papillary and middle dermis. The mast cells were round and oval, with abundant granular cytoplasm and a central nucleus. The cytoplasmic granules of the mast cells stained metachromatically with Giemsa stain (Figure 3). These findings were consistent with the diagnosis of cutaneous mastocytosis.