BACKGROUNDExtranodal natural killer/T-cell (NK/T cell) lymphoma, nasal-type, is a rare lymphoma. Skin is the second most common site of involvement after the nasal cavity/nasalpharynx. The aim of this study was to investigate the clinicopathologic features, immunophenotype, T cell receptor (TCR) gene rearrangement, the association with Epstein-Barr virus (EBV) infection and p53 gene mutations of the lymphoma.

METHODSThe clinicopathologic analysis, immunohistochemistry, in situ hybridization for EBER1/2, TCR gene rearrangement by polymerase chain reaction (PCR), mutations of p53 gene analyzed by PCR and sequence analysis were employed in this study.

RESULTSIn the 19 cases, the tumor primarily involved the dermis and subcutaneous layer. Immunohistochemical staining showed that most of the cases expressed CD45RO, CD56, CD3ε, TIA-1 and GrB. Three cases were positive for CD3 and two cases were positive for CD30. Monoclonal TCRγ gene rearrangement was found in 7 of 18 cases. The positive rate of EBER1/2 was 100%. No p53 gene mutation was detected on the exon 4 - 9 in the 18 cases. Fifteen cases showed Pro (proline)/Arg (arginine) single nucleotide polymorphisms (SNPs) on the exon 4 at codon 72. The expression of p53 protein was 72% (13/18) immunohistochemically.

CONCLUSIONSCutaneous NK/T-cell lymphoma is a rare but highly aggressive lymphoma with poor prognosis. No p53 gene mutation was detected on the exon 4 - 9, and Pro/Arg SNPs on p53 codon 72 were detected in the cutaneous NK/T-cell lymphoma. The overexpression of p53 protein may not be the result of p53 gene mutation.