Presumed ocular juvenile xanthogranuloma and biopsy-proven cutaneous mastocytosis occurring sequentially in a young boy.

Juvenile xanthogranuloma is a benign non-Langerhans cell histiocytosis characterized by skin lesions that tend to be self-limited. Ocular lesions can occur in juvenile xanthogranuloma, most commonly presenting as an iris granuloma. Skin lesions of juvenile xanthogranuloma may appear similar to lesions of mastocytosis. Mastocytosis includes a heterogeneous group of diseases characterized by the proliferation and abnormal infiltration of mast cells. Rubbing of cutaneous lesions leads to the release of histamine, causing the lesions to urticate. Juvenile xanthogranuloma and mastocytosis skin lesions occurring concurrently is extremely rare, with only four cases reported. Ocular juvenile xanthogranuloma and cutaneous lesions of mastocytosis have never been described in the same patient in the literature. The authors describe a patient with an ocular juvenile xanthogranuloma presenting at birth with cutaneous mastocytosis developing several years later.