[Xanthelasmoid mastocytosis: a rare form of cutaneous mastocytosis]

Mastocytosis is a rare disease characterized by the abnormal accumulation of mast cells in the skin and possibly in other organs. It can occur in a variety of forms; xanthelasmoid mastocytosis(XM) is a very rare form classified as papulo-nodular. Clinically, it appears as buff-yellow soft papules or nodules of variable size. Triggerings are those of classic mastocytosis. Darier's sign is often absent. Histology shows dense infiltrate of mast cells in the deep dermis. This clinical form can be singled out because of the persistence of lesions beyond puberty without the additional risk of systemic involvement. We here report the case of a 18-month old female infant, with no previous medical history. Maculopapular, intensely pruritic, ovalaires, brownish lesions with a buff-yellow centre, with elastic consistency and different sizes first occurred at the age of 8 months. The initial interview of parents revealed that the infant had had episode of flush especially caused by warmth. Darrier's sign was negative. Skin biopsy showed dermal infiltrate of mast cells, allowing to retain the diagnosis of xanthelasmoid mastocytosis. Complementary examinations as well as trypsin dosage were normal. Treatment was based on the exclusion of drugs and of factors participating in mast cells degranulation and antihistamines.