Lymphomatoid papulosis misdiagnosed as pityriasis lichenoides et varioliformis acuta: Two case reports and a literature review.

The aim of this study was to improve the level of diagnosis and differential diagnosis of lymphomatoid papulosis (LyP). Two cases of type B LyP were identified and the literature was reviewed to summarize the clinical outcomes and pathology of LyP and its treatment. The two patients exhibited symptoms with papulonodular lesions, the centers of which gradually underwent ulceration and necrosis. CD30, a helper T-cell marker specifically expressed in tumor cells was analyzed by immunohistochemical staining and the result showed that CD30-negative or only scattered CD30-positive cells were present. Therefore, a diagnosis of type B LyP was made. A fairly good curative effect was achieved following treatment with retinoic acid, glucocorticoids and immunomodulatory drugs. LyP is a type of low-level malignant lymphoma and is easily misdiagnosed as pityriasis lichenoides et varioliformis acuta and other diseases. In order to avoid under diagnosis and misdiagnosis, doctors should evaluate suspected patients by histopathological and immunohistochemical examination.