Systemic mastocytosis with diffuse cutaneous involvement and haematological disease presenting in utero treated unsuccessfully with vincristine.

Mastocytosis is a disorder characterised by abnormal mast cell proliferation. The diverse spectrum of clinical presentations is dependent on the tissues and organs involved. We report a rare case of aggressive systemic mastocytosis presenting in utero with diffuse cutaneous involvement, and haematological abnormalities. There is little published evidence to guide treatment.