Differential Diagnosis of CD30 Expression

CD30 is an activation marker that is characteristically expressed by cutaneous CD30-positive lymphoproliferative disorders (lymphomatoid papulosis and anaplastic large cell lymphoma). However, CD30 is not specific for these entities and may show significant expression in a variety of benign and malignant cutaneous lymphoid infiltrates. The identification of CD30 expression by itself is not enough to make a diagnosis. Additional immunophenotyping and clinical correlation are necessary for proper classification.