Cutaneous mastocytosis: pediatric approach to solitary mastocytoma

Cutaneous mastocytosis is an uncommon disease characterized by clonal mast cell proliferation limited to the skin that predominantly affects children. Solitary mastocytoma is the second most frequent variant and usually has a benign, self-limited course, and its recognition is essential to avoid unnecessary invasive studies. We present the case of a previously healthy girl aged 1 year and 6 months presenting with a single lumbar skin lesion that appeared in early infancy. The lesion was an erythematous-brown macule-plaque with friction-induced blistering and a positive Darier sign, without systemic symptoms. A clinical diagnosis of solitary mastocytoma was established. Treatment included a topical corticosteroid, a topical calcineurin inhibitor, and general measures, resulting in a favorable outcome. Pediatric solitary mastocytoma is infrequent and has an early onset and an excellent prognosis. The diagnosis is clinical and the management conservative, avoiding unnecessary procedures, in addition to appropriate family counseling and long-term follow-up.