KIT and systemic mastocytosis: The V560G <i>KIT</i> mutation is extremely rare in patients with SM and its biological and prognostic impact remains unknown.<h4>Case presentation</h4>A 15-year old boy was referred to our hospital because of repeated episodes of flushing, hypotension and syncope since the age of 3-years, preceded by skin lesions compatible with mastocytosis on histopathology that had disappeared in the late-early childhood.