Cutaneous anaplastic large-cell lymphoma should be evaluated for systemic involvement regardless of ALK-1 status: case reports and review of literature.

Anaplastic large-cell lymphoma (ALCL) is a lymphoma that expresses CD30. Cutaneous ALCL presents either as primary cutaneous disease or as secondary skin involvement due to the systemic disease. Herein, we describe two patients who presented to dermatology for evaluation of skin lesions diagnosed by non-dermatologists as a cutaneous abscess and lupus erythematosus, respectively. Upon investigation by a team of medical dermatologists and dermatopathologists, systemic ALCL with secondary skin involvement was discovered in both patients. The majority of cases of systemic ALCL with cutaneous involvement express anaplastic lymphoma kinase-1 (ALK-1), and are associated with a more favorable prognosis than ALK-1-negative cases. However, cutaneous ALCL regardless of ALK-1 status may be secondary to systemic lymphoma. This article stresses the importance of dermatologists being aware of the diagnosis of systemic lymphoma based on cutaneous findings, and being aggressive in initiating appropriate diagnostic testing. Primary cutaneous ALCL and systemic ALCL are reviewed.