A 50-year-old woman presented with a subcutaneous tumor extending from the right axilla to the scapula; she also had eosinophilia and nephrotic syndrome. The tumor was histopathologically diagnosed as mimic angiolymphoid hyperplasia with eosinophilia (ALHE).
In the biopsy specimens from the skin and kidney, IgG4-positive plasma cells infiltrated, leading to the diagnosis of IgG4-related disease. IgG4-related disease and ALHE share the same Th2-skewing immunological condition. Our case indicates that subcutaneous ALHE is one of the skin manifestations that can be due to IgG4-related disease.