Superficial and deep infiltrating congenital juvenile xanthogranuloma involving multiple skeletal muscles and associated with ulceration and generalized postinvolution atrophy.

We present a 2-day-old boy with a deep-seated giant juvenile xanthogranuloma infiltrating the skeletal muscles on his right lower limb. Unlike typical juvenile xanthogranuloma, the lesion has shown only partial spontaneous regression with large atrophic scar. However, despite the involvement multiple muscle on the right thigh, the patient has no evidence of orthopaedic sequelae.