Primary cutaneous anaplastic large cell lymphoma

Primary cutaneous anaplastic large cell lymphoma (PC‐ALCL) is a CD30+ lymphoproliferative disorder (LPD) of the skin with a relatively good prognosis in the absence of high‐stage disease. CD30+ LPDs comprise approximately 25%‐30% of primary cutaneous lymphomas and as a group represent the second most common clonal T‐cell neoplasm of the skin behind mycosis fungoides. Diagnosis of PC‐ALCL relies strongly on clinicopathologic correlation given the potential morphologic, clinical and molecular overlap with the other cutaneous CD30+ LPD, lymphomatoid papulosis, and more aggressive hematolymphoid neoplasms.