Leukemic phase of primary cutaneous anaplastic large-cell lymphoma (ALK-negative), with downregulation of CD30

Leukemic phase of anaplastic large cell lymphoma (ALCL) is extremely rare. We present a case of primary cutaneous-ALCL (C-ALCL), who developed nodal involvement 4 years later. The patient was treated with combination chemotherapy and autologous stem cell transplantation; however, she relapsed 5 months later. At that time, the patient was given brentuximab vedotin (BV) with initial response. One year later, the patient demonstrated progressive adenopathy and leukemic involvement by her ALCL (comparative T cell clonality showed PCR products of the same size in the diagnostic skin and relapsed leukemic blood). Interestingly, the circulating tumor cells showed only subset expression of CD30 by flow cytometry (performed on peripheral blood). This patient demonstrates an unusual manifestation of ALCL (leukemic phase), with the additional confounder of CD30 downregulation, perhaps secondary to the BV therapy, or possible CD30-negative tumor escape.