Transformation of vulvar pseudolymphoma (lymphoma-like lesion) into a marginal zone B-cell lymphoma of labium majus.

Lymphomas arising in the female genital tract are extremely uncommon. Diffuse large B-cell lymphoma and follicular lymphoma are the most common types. We describe the case of an 80-year-old woman with a recurrent lesion in the vulva initially diagnosed as a lymphoma-like lesion and evolving 7 years later into a marginal zone B-cell lymphoma (lymphoplasmacytic lymphoma). Diagnosis was based on the monotypic pattern of the plasmacellular component and the clonal rearrangement of immunoglobulin heavy chain genes. No previous cases of vulvar marginal zone B-cell lymphoma arising in the context of a persistent lymphoma-like lesion have been reported. We highlight the importance of differentiating benign from malignant lymphoid infiltrates in the vulva.