Neonatal mastocytosis with pachydermic bullous skin without c-Kit 816 mutation.

BACKGROUND: Bullous mastocytosis is an unusual variant of mast cell disease with widespread bullae as the main cutaneous feature induced by mast cell proteases that cause dermoepidermal separation. CASE REPORT: A rare case of diffuse cutaneous bullous mastocytosis with pachydermia and unusually extensive skin folding is described in a 3-week-old girl. The diagnosis was confirmed by immunohistochemistry with Giemsa stain, the naphthol ASD chloroacetate esterase reaction and elevated blood levels for tryptase, histamine in serum and histamine and 1.4-methylimidazol acetic acid in the 24-hour urine. Blood cell count was normal, as were thrombocytosis and leukocytosis. FACS analysis of the bone marrow aspiration material showed 1% mast cells. No c-Kit 816 [Asp-->Val] somatic mutation was found. Systemic involvement of other organs was excluded. DISCUSSION: The prognosis of c-Kit-negative diffuse bullous mastocytosis is not known. Regular blood controls are mandatory, and screening for germ cell ovarian cancer and bone marrow controls should be performed as well. Copyright (c) 2006 S. Karger AG, Basel.