Immunoglobulin gene analysis of cutaneous pseudolymphoma by polymerase chain reaction.

Polymerase chain reaction (PCR) was used to amplify the V-D-J region of the immunoglobulin heavy chain gene from DNA extracted from the formalin fixed, paraffin embedded skin of 3 cases of pseudolymphoma. The products were electrophoresed and observed under ultraviolet light after ethidium bromide staining. Specimens of two cases showed smears of polyclonal amplified DNA. The specimen of one case (Case 3), however, showed a single band with a smear. The presence of monoclonality in B lymphocyte populations may suggest the possibility of low grade malignancy of pseudolymphoma or transformation to malignant lymphoma in the future.