Dystrophic xanthomatization after radiotherapy for primary cutaneous anaplastic large cell lymphoma

An 83-year-old woman noticed multiple red tumors on her left ear three months before her first visit to our department. Clinically, multiple reddish tumors were present on the preauricular area of her left ear. Histologically, CD30-positive and ALK-negative large or medium-sized atypical lymphocytes proliferated in the entire dermis with massive inflammatory small lymphoid cell infiltration. The patient had no extracutaneous lesions including bone marrow ; therefore, she was diagnosed with primary cutaneous anaplastic large cell lymphoma (PCALCL). Electron beam-irradiation therapy at the total dose of 40 Gy led to complete remission of all the tumors ; however, yellowish nodules remained on the affected area. Histologically, numerous foamy cells were found in the dermis without any CD30+ atypical tumor cells, supporting the diagnosis of dystrophic xanthomatization caused by radiation therapy for PCALCL. We also summarize and discuss the characteristics of six other reported cases of dystrophic xanthomatization associated with PCALCL.