A Case of S‐100‐Positive Juvenile Xanthogranuloma: A Longitudinal Observation

Abstract

We present the case of a 9-month-old boy with yellow-brown papules that gradually increased in number over a period of 6 months without systemic involvement. Our case was clinicopathologically diagnosed as S-100-positive juvenile xanthogranuloma, and longitudinal observation revealed that strong S-100 reactivity disappeared in parallel with maturation of the lesions within 2 years after the initial diagnosis. These findings add to the complexity in cells of origin of this disorder.