Spontaneous regression of cutaneous blastic plasmacytoid dendritic cell neoplasm followed by acute monocytic leukemia evolving from myelodysplastic syndrome.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematologic malignancy arising from plasmacytoid dendritic cell precursors. BPDCN typically manifests in the skin, but it can also evolve into a leukemic form or be complicated by acute myeloid leukemia, some cases with a preceding myelodysplastic syndrome (MDS). We herein report the first case of complete spontaneous regression of cutaneous BPDCN followed by acute monocytic leukemia evolving from MDS. This is also the first reported case of gastric BPDCN invasion.