Subcutaneous Panniculitis-like T-cell Lymphoma: A Study Of Clinicopathology, Immunophenotype, Gene Rearrangement And Epstein-Barr Virus Infection

Background and Objective Subcutaneous panniculitis-like T-cell lymphoma (SPTL) is a rare and special type of cutaneous lymphoma. Recent studies indicated that there are two types of SPTL, one isα/βT-cell phenotype and the other isγ/δT-cell phenotype. Both showed differences in clinicopathology, immunophenotype, and T cell receptor (TCR). The term "SPTL" was only used for cases with anα/βphenotype in the 2005 WHO-EORTC classification for cutaneous lymphomas. A retrospective study of 20 case SPTL was carried out in clinicalpathology, immunophenotype, gene rearrangement and Epstein-Barr virus (EBV) detection in our research group according to the 2005 WHO-EORTC classification of cutaneous lymphomas. The aim of our research was to observe the clinicopathological features of SPTL, and to explore the significance of immunophenotype and gene rearrangement in the diagnosis of SPTL. The relationship between EBV infection of SPTL and p53 protein expression was analyzed in this tumor as well.Materials and Methods Twenty cases of SPTL were selected from the archives in Pathological Laboratory of Department of Dermatology and Department of Pathology from 1985 to 2006. The clinical materials and follow-up results were collected, and histopathological changes were re-evaluated according to the WHO-EORTC classification for cutaneous lymphomas. Immunohistochemical staining forβF1, CD2, CD3, CD45RO, CD4, CD8, CD20, CD30, CD56, p53, polymerase chain reaction for TCRγand IgH gene rearrangement, and in situ hybridization for EBER1/2 were performed for all of the cases. Statistics analysis was used for the relationship between EBV infection and p53 protein expression in this tumor.Results (1) Clinical manifestations: The cases of SPTL tended to present in young adults. The median age was 29.5 and the range from 10 to 55 years old. No gender predilection was found. Patients presented with nodules or subcutaneous masses generally, which mostly involved the legs. Systemic symptoms were found in 61.1% and in which fever was the most common in these cases. (2) Histopathology: The main histopathologic changes of SPTL were in the subcutaneous layer and the infiltration pattern was in the panniculitis-like in this layer. The rimming of adipocytes caused by tumor cells infiltrating was observed in all cases. The tumor cells were in multiform, atypia and in different size. Most of the cases (75.0%) hold the medium-sized cells predominantly. There were some necrosis, karyorrhexis, beanbag cells, erythrophagocytosis, and angioinvasion in the tumor. (3) Immunophenotype: All cases expressed one to three T-cell-associated antigens (CD2, CD3, or CD45RO). Most cases were positive forβF1 (94.7%), CD8 (90.0%), Granzyme B (80.0%) and TIA-1 (100.0%) . All cases didn't express CD4, CD20, CD56 and CD68. (4) Gene rearrangement: Two groups of consensus primers for TCRγgene was used to detect the TCRγgene rearrangement. Monoclonal TCRγgene rearrangement was found in 16 of 20 cases (80.0%) while no IgH gene rearrangement was detected in all cases. (5) EBV and p53 protein: In the 20 cases of SPTL, the positive rate of EBER1/2 was 25.0% and that of the p53 protein expression was 30.0%. The two rates showed correlated statistically (P < 0.05).Conclusions (1) SPTL is a distinctive lymphoma which mainly involved the subcutaneous tissue clinicopathologically. It may signify the poor prognosis of SPTL if the patient has skin lesion ulceration, tumor dissemination, hemophagocytic syndrome and the tumor cells epidermotropism. (2) TCR subset analysis should be performed in order to confirm the diagnosis of SPTL. An antibody panel recommended for the SPTL diagnosis isβF1, CD4, CD8, CD2, CD3, CD45RO, TIA-1 and CD20. (3) The neoplastic cells of SPTL show clonal TCR gene rearrangements. It's necessary to collecting the clinical, histologic, immunophenotypic and gene rearrangement data to confirm the diagnosis of SPTL. (4) Some of SPTL are accompanying with EBV latent infection, which may signify a poor prognosis in these cases. The expression of p53 protein might be related to the EBV infection in SPTL.