Polymerase chain reaction analysis of immunoglobulin gene rearrangement in cutaneous lymphoid hyperplasias. French Study Group for Cutaneous Lymphomas.

UNLABELLED: The differential diagnosis of cutaneous lymphoid hyperplasia and B-cell lymphoma may be difficult. Whether the detection of clonal immunoglobulin gene rearrangement in the cutaneous lesion is predictive of a malignant outcome remains controversial. We therefore studied cases of cutaneous lymphoid hyperplasia by polymerase chain reaction analysis.

DESIGN: Retrospective study of patients seen between 1988 and 1996.

SETTING: Two dermatology university departments.

PATIENTS: Twenty-four patients with cutaneous lymphoid hyperplasias were included according to clinical, histopathological, and immunophenotypic criteria.

MAIN OUTCOME MEASURES: Clinical, histopathological, and laboratory findings.

RESULTS: There were 13 men and 11 women (mean age, 49 years) who presented with erythematous or violaceous papules or nodules. The lesions were unique in 13 cases and multiple in 11 cases. All patients had immunochemical evidence of a mixed T- and B-cell infiltrate with polytypic B cells. Polyclonality was demonstrated in 23 patients, whereas a dominant B-cell clone was detected in 1 patient. No lymphoma developed during the follow-up (median, 4 years). In the same period, we studied 53 cases of B-cell lymphomas. Thirty-five (66%) of the 53 cases had a detectable clonal immunoglobulin gene rearrangement.

CONCLUSIONS: In the majority of our cases, polyclonality demonstrated by polymerase chain reaction analysis was in accordance with the diagnosis of cutaneous lymphoid hyperplasia. In 1 of the 24 patients, the presence of a B-cell clone could be evidenced. This fact did not modify the treatment as there were no histological or immunophenotypic signs suggestive of a lymphoma.