Paraneoplastic Pemphigus Associated with B-cell Chronic Lymphocytic Leukemia Treated with Ibrutinib and Rituximab.

Paraneoplastic pemphigus (PNP) is a severe autoimmune blistering disease associated with an underlying malignancy, and its prognosis is poor. We herein report the first patient with B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma (B-CLL/SLL)-associated PNP successfully treated with the Bruton's tyrosine kinase inhibitor ibrutinib and rituximab. Although his PNP lesions did not improve with ibrutinib monotherapy, the combination of ibrutinib and rituximab was effective against B-CLL/SLL-associated PNP. This case suggests that ibrutinib plus rituximab may be a potent therapeutic option for B-CLL/SLL-associated PNP that is hard to control with ibrutinib alone.