Sean Klepper M.D.
Stephen Lyle, M.D., ...
Also known as: cutaneous B-cell lymphoid hyperplasia, lymphadenosis benigna cutis, lymphocytoma cutis, pseudolymphoma of Spiegler-Fendt
- Reactive proliferation of B-cells
- May be secondary to a variety of immune provocations, such as insect bites, drugs, vaccinations, tattoos and infection with Borrelia burgdorferi.
- Common sites are the face, nipple and scrotum.
- Presents as a solitary, smooth, red to brown nodule.
- Well-circumscribed nodular collections of predominantly small mature lymphocytes within the dermis and sometimes subcutis
- The nodules are frequently more densely packed within the upper dermis than the lower dermis ("top heavy").
- Germinal centers are frequently present.
- Important in the differential diagnosis with lymphoma is the admixture of smaller numbers of other cell types within the lymphoid collections: eosinophils, plasma cells and histiocytes.
- The epidermis and adnexae are uninvolved, in contrast to lymphoma.
- Mitotic figures are rare, except in germinal centers.
- The B-cells stain for the usual B-cell markers (CD20, CD19. CD79a) and are polytypic for immunoglobulin light chains (kappa and lambda). They are usually surrounded by numerous CD3+ T-cells.