LYMPHOMA VERSUS PSEUDOLYMPHOMA OF THE SKIN - GENE REARRANGEMENT STUDYOF 21 CASES WITH CLINICOPATHOLOGICAL CORRELATION

Background- Diagnosis of cutaneous lymphoma in the absence of systemic lymphoma may be difficult. Reactive lymphoid lesions can mimic lympho ma clinically and histologically and have been designated pseudolympho mas. Objective: Our purpose was to analyze lymphoid gene rearrangement s in cutaneous lymphoproliferative lesions and to correlate these find ings with the histologic, immunophenotypic, and clinical profile. Meth ods: We examined 21 cases of lymphoproliferative lesions that develope d in skin and performed molecular rearrangement analysis of T-cell rec eptor and immunoglobulin genes. We examined identical tissues by histo logic and immunophenotypic criteria and conducted follow-up clinical e valuation of all patients. Results. Clonal rearrangements of immunoglo bulin (seven cases) or T-cell receptor (two cases) gene were detected in 9 of 21 patients. No specific histologic or immunophenotypic featur e was consistently associated with a clonal lymphoid gene rearrangemen t. Systemic lymphoma developed in one patient in whom a clonal rearran gement within the immunoglobulin gene was identified. Conclusion: Gene rearrangement analysis may be helpful in differentiating primary cuta neous lymphoma from pseudolymphoma. The chronic clinical course of pat ients with clonal lymphoid gene rearrangements supports a lack of corr elation between clonality and biologic aggressiveness.