Rituximab as a dual therapeutic option for pemphigus and primary cutaneous B‐cell lymphomas: Two case reports

Abstract

It is known that individuals with immune dysregulation have an increased risk of non‐Hodgkin lymphoma. This association has been proven for pemphigus as well as for other autoimmune disease. We describe the development of cutaneous B‐cell lymphoma in two patients affected by long‐standing pemphigus vulgaris and pemphigus foliaceus (i.e., characterized by histological and immunopathological features different from those of paraneoplastic pemphigus). In both cases, a therapy with rituximab allowed to achieve the complete remission for the lymphoproliferative disease (never recurred at follow up) and a substantial long‐term improvement of the clinical manifestations of pemphigus, although persistent to serological disease and occasional recurrences. We suggest that clinicians should consider that patients with long‐standing pemphigus, both vulgaris and foliaceus, may develop primary cutaneous B‐cell lymphomas, as shown in our report, and in these cases the treatment with rituximab is elective, providing a therapeutic option for both low‐grade or follicular, CD20‐positive, B‐cell non‐Hodgkin lymphomas and pemphigus. Nevertheless, as shown in our cases, a constant surveillance for pemphigus is necessary.