A Review of Primary Cutaneous CD30 + Lymphoproliferative Disorders.

Primary cutaneous CD30+ lymphoproliferative diseases (LPDs) comprise a range of diseases (LyP, pcALCL, and borderline lesions) with broad histologic and phenotypical characteristics, although they all share the common feature of a favorable prognosis notwithstanding histology suggestive of a high-grade lymphoma. Given their cytomorphologic similarities, accurate diagnosis and workup are needed to differentiate these distinct entities in order to best use novel biologic therapies and avoid aggressive overtreatment. Moreover, although CD30+  LPDs have a favorable prognosis, secondary malignancies should be considered as part of the initial evaluation, and patients should have ongoing surveillance.