[Lymphomatoid papulosis type C or transition to CD30+-T-cell lymphoma? A difficult differential diagnosis].

Lymphomatoid papulosis (LyP) is a recurrent papulonodular eruption, characterized by self-healing skin lesions. While this disorder usually has a benign course, about 10% of the patients develop lymphoproliferative disorders such as CD30+ T cell lymphoma. We report 2 patients with LyP type C. In one case progress to a cutaneous CD30+ large T cell lymphoma could not be excluded. Histologic differentiation between LyP and malignant lymphoma causes considerable problems. In this regard, the evaluation of the clinical course is essential. A long-term follow-up including diagnostic imaging studies is required.