Intracardiac juvenile xanthogranuloma in a newborn.

Juvenile xanthogranuloma (JXG) presents a normolipemic non-Langerhans cells histiocytosis. JXG usually presents with cutaneous lesions. Visceral involvement is rare but may affect various organs. Deep JXG differs histologically from the cutaneous form by its tendency to consist solely of homogeneous proliferation of histiocytes without any xanthomatous or Touton giant cells. Awareness of the possibility of this atypical presentation of JXG helps in making the correct histologic diagnosis, which is supported by proving adequate immunomarkers on histiocytes (mainly PG-M1, an antibody against the CD68 antigen). JXG may present with intramuscular lesions only; however, rarely JXG has been reported to affect the heart but not without the typical cutaneous manifestations. We present an unusual case of deep JXG without systemic disease or metabolic abnormalities. To our knowledge, this is a first reported case of intracavitar JXG without skin lesions.