Coexistence of pemphigus vulgaris, malignant melanoma and low-grade lymphoma.

A 53-year-old female patient with pemphigus vulgaris under continuous immunosuppressive therapy for about 2 years presented a superficial spreading malignant melanoma on a pre-existing melanocytic naevus. After surgical removal of the inguinal lymph node group, a diffuse low-grade polymorphous immunocytoma was proved both histologically and immunocytochemically. The possible induction mechanisms are discussed.