Prolonged severe pancytopenia preceding the cutaneous lesions of juvenile xanthogranuloma.

We report a case of juvenile xanthogranuloma (JXG) having progressive pancytopenia for 6 months until the proliferating skin lesions. A 2-month-old infant presented recurrent fever, anemia, and hepatosplenomegaly mimicking hemophagocytic lymphohistiocytosis (HLH) or juvenile myelomonocytic leukemia (JMML). At 8 months of age, the biopsy of a growing papule on the elbow made the diagnosis. Bone marrow (BM) specimens showed clustering foamy cells including hemophagocytosis by histiocytes. Treatment with etoposide followed by vinblastine plus prednisolone (PSL) therapy improved the disease. Although JXG is a benign non-Langerhans cell histiocytosis, the multisystem-visceral form should be considered as a potential aggressive disease when associated with BM failure in early infancy.