A comparative study between subcutaneous panniculitis-like T-cell lymphoma and cutaneous extranodal nasal-type NK/T cell lymphoma / 肿瘤

ABSTRACT

Objective:To compare the difference between 20 cases of subcutaneous panniculitis-like T-cell lymphoma (SPTL) and 19 cases of cutaneous extra-nodal nasal-type NK/T-cell lymphoma (cutaneous NK/T-cell lymphoma). Methods:The two types of lymphoma were compared in clinical pathology, immunological marker, Epstein-Barr (EB) virus infection, and T-cell receptor (TCR) gene rearrangement. Results:Differentiated diagnosis of the two types of lymphomas was not easy based on their clinical manifestations,but the cutaneous NK/T-cell lymphoma was always followed by extracutaneous dissemination and had a poor prognosis. Histopathologically, SPTL was usually limited in subcutaneous fatty tissues while the cutaneous NK/T-cell lymphoma showed diffused infiltration around the dermis and it often infiltrated into the subcutaneous fat tissues. Coagulation necrosis, angiocentric infiltration and epidermotropism were often observed in cutaneous NK/T-cell lymphoma. When compared with immunophenotypes, SPTL often expressed βF1, membrane CD3 and CD8 but did not express CD4 and CD56, while most of the cutaneous NK/T-cell lymphomas expressed CD56 and cytoplasm CD3ε and only a few cases expressed CD3 and CD8. The differences in the expression of CD56, CD3, CD8, and βF1 were significant between the two types of lymphomas(P<0.05). The positive rate of EBER1/2 was 25% (5/20) in SPTL while it was 100% in cutaneous NK/T-cell lymphoma. The difference was statistically significant (P<0.05). Monoclonal TCR-γ gene rearrangement was found in 16 out of 20 cases of SPTL (80%) but only in 4 of 18 cases in the cutaneous NK/T-cell lymphoma (22.2%). The difference was significant(P<0.05). Conclusion:The key points to distinguish the two lymphomas are (1) extracutaneous dissemination, coagulation necrosis, angiocentric infiltration and epidermotropism; (2) the expressions of CD56, CD3, CD3ε, CD8, and βF1; (3) the positivity of in situ hybridization of EB virus; (4) detection of the monoclonal TCR-γ gene rearrangement. To make an acute differentiated diagnosis of the two lymphomas, comprehensive analysis is necessary to integrate the results of clinical manifestation, histopathology, immunophenotype, infection of EB virus and gene rearrangement.