Cutaneous involvement by angioimmunoblastic T-cell lymphoma with remarkable heterogeneous Epstein-Barr virus expression

Introduction: Initially described as an abnormal immune reaction, most cases of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD)-like T-cell infiltrates are now regarded as a peripheral T-cell lymphoma (AILD T-NHL). AILD T-NHL is characterized clinically with constitutional symptoms, generalized lymphadenopathy, hepatosplenomegaly, skin rash, and polyclonal hypergammaglobulinemia. Epstein-Barr virus (EBV) is frequently detected in involved lymph nodes, but the presence of EBV in cutaneous infiltrates of AILD T-NHL has rarely been examined. We present a patient with AILD T-NHL with cutaneous involvement that shows marked heterogeneity of EBV expression in the lymph node and skin biopsies, and review the histological findings of AILD T-NHL in the skin. Methods: Two skin biopsies of a diffuse maculopapular rash and a lymph node were examined and immunophenotyped. In situ hybridization for detection of EBV in the lymph node and skin biopsies was utilized. In order to attempt to delineate which lymphocytes were EBV positive, skin biopsies were dual labeled with CD3, CD45RO, CD20 and EBV. The skin biopsies and lymph node were submitted for gene rearrangement studies by polymerase chain reaction (PCR). Capillary electrophoresis of fluorescently labeled PCR products was utilized for PCR product quantitation. Results: The histological features of the lymph node were diagnostic of AILD T-NHL and a T-cell clone was identified by PCR. The skin biopsies showed an atypical superficial and deep perivascular polymorphous infiltrate consistent with cutaneous involvement by AILD T-NHL. Both skin biopsies showed the same clonal T-cell receptor gene rearrangement as the lymph node. In situ hybridization of the lymph node and one skin biopsy showed a few scattered EBV-positive lymphocytes (≤1% of the infiltrate). A second skin biopsy revealed 40-50% of the lymphocytes as EBV positive. Dual staining for CD20 and EBV identified a minority of EBV-infected lymphocytes as B-cells, but most of the EBV-positive cells lacked staining for CD3 and CD45RO. Conclusions: In our patient, the same T-cell receptor gene rearrangement was found by PCR in all three biopsy sites. Most cases of AILD T-NHL contain only a few EBV-positive cells, but in our patient the extent of EBV expression ranged from ≤1% to 40-50% of the AILD T-NHL cutaneous infiltrate. To our knowledge, this case is the most extensive and heterogeneous expression of EBV in cutaneous AILD T-NHL to date.