Analysis of T-cell receptor rearrangements and microarrays in pediatric patients with cutaneous lymphoma

Cutaneous lymphomas (CL) are rare in pediatric patients and are mostly represented by mycosis fungoides and CD30+ lymphoproliferative disorders (lymphomatoid papulosis [LYP] and anaplastic large T-cell lymphoma [ALCL]). CL in children should be differentiated from benign skin disorders. The purpose of our study was to investigate the role of T-cell receptor analysis by using the BIOMED-l and BIOMED-2 primer sets for complete and incomplete TCR delta, gamma and beta rearrangements. We collected DNA samples from frozen skin biopsies of 31 patients less than 18 years of age: 7 mycosis fungoides (MF), 8 parapsoriasis (PS), 10 LYP and 2 ALCL, 2 subcutaneous panniculitis-like CD8+ alpha:beta T-cell lymphoma (SPTL) and 2 CD4+ small/medium sized pleomorphic T-celllymphoma (PTL). All MF and 2/8 parapsoriasis presented clonal rearrangements. In the CD30+ lymphomas, clonal rearrangements were observed in 9/10 LYP and 1/2 ALCL. Four pediatric patients, presented rare entities (SPTL and PTL) and all cases were clonal. The presence of a T-cell clone was confirmed by sequencing in 17 patients. In one MF case, we detected the presence of the same clone in skin and peripheral blood, while in 2 cases (PTL and PS) different clones were found in different skin biopsies. Overall, we found clonal rearrangements in 23 patients, confirmed by sequencing of the TCR genes in 17/23. These data suggest the higher sensitivity of the more complete screening (delta, gamma and beta) and the utility of the sequencing procedures. Finally some MF, LYP, CD30+ aggressive cases were studied by arrays-CGH showing alterations of the genome in three cases, such as: trisomy of chromosome 7 (CD30+) and 19 (CD8+); duplication of 22 (CD8+); deletion of TCRA/D (SPTL). No genomic imbalance were demonstrated in the analyzed cases of PS or LYP. Three of our patients died of disease: one of MF progressing to erythroderma, blood and lymph nodes; the second of SPTL complicated by haemophagocytic syndrome; the third of CD30+, CD8+ ALCL for dissemination and visceral involvement. Due to the highly variable presentations of these malignancies and to the relevance of prognostic issues in children, we conclude that molecular assessment can be very important to improve diagnosis of these diseases.