Giant Juvenile Xanthogranuloma: Case Report, Literature Review, and Algorithm for Classification.

Juvenile xanthogranuloma (JXG) is a member of the non-Langerhans cell group of proliferative disorders of mononuclear phagocytes. JXG is a benign tumour of histiocytic cells. Classic JXG is divided into 2 main clinical subtypes: dome-shaped papules (<0.5 cm) and single/multiple nodules (<2.0 cm). A rare variant is referred to as giant; this term encompasses JXG lesions larger than 2.0 cm. In this article, we report a case of a congenital cutaneous giant JXG. In addition, we reviewed and analyzed all cases (n = 51) of giant JXG reported in the English literature. We propose an algorithm for classifying giant JXG based on the following factors: onset of lesions (congenital and acquired), number of lesions (solitary ± satellites and multiple), morphology of cutaneous/mucosal lesions (plaque, nodular, ulcerated-nodular, macular, and other), and extracutaneous manifestations.