Abstract: Pityriasis rubra pilaris is a rare scaly keratosis skin disease, and its pathogenesis may be related to tumor and other factors. A case of pityriasis rubra pilaris was misdiagnosed as psoriasis, and later developed into erythroderma. An anterior mediastinal mass was found with elevated carcinoembryonic antigen levels during diagnosis and treatment. After oral acitretin and tumor resection, the rash resolved. Postoperative pathology and immunohistochemistry showed schwannoma.

Key words: pityriasis rubra pilaris')">">pityriasis rubra pilaris, erythroderma, anterior mediastinal mass, schwannoma