Paraneoplastic pemphigus with clinical features of lichen planus associated with low-grade B cell lymphoma.

BACKGROUND Neoplasia-induced lichen planus is described as a cell-mediated reaction to unknown epithelial antigens. Paraneoplastic pemphigus (PNP), characterized by the presence of a specific array of autoantibodies, probably represents a different form of presentation of the same autoimmune syndrome where the mucocutaneous expression depends on the dominant pathologic mechanism. METHODS The authors report a case of PNP with predominant lichen planus-like lesions and review the relevant literature. We observed a 74-year-old female with vesico-bullous, erosive, target-shaped and flat papular lichenoid lesions on the lower legs, palms and soles, evolving for 3 weeks. Histopathology revealed a lichenoid dermatitis. Direct immunofluorescence showed C3 deposition around keratinocytes and epidermal IgG intranuclear deposition. Indirect immunofluorescence revealed circulating IgG with intercellular staining on rat bladder substrate. Immunoblotting demonstrated bands of 130, 190, 210 and 250 kDa antigens. A pararenal B cell lymphoma was found. RESULTS Oral corticotherapy with 40 mg prednisolone daily was initiated with a good cutaneous response. Four months later, cyclophosphamide (50 mg/day) was introduced because of a discrete enlargement of the pararenal mass. The patient died on the seventh month of follow up as a result of respiratory insufficiency. CONCLUSION PNP has different forms of presentation and the lack of a consensus about diagnostic criteria may contribute to underdiagnosed cases. Advances on the knowledge of the sensitivity and specificity of diagnostic criteria have allowed a better accuracy of diagnosis.