A Patient with Myxoid/Round Cell Liposarcoma (MRCL) Involving the Well-known Translocation t(12;22): A Case Report with the Cytogenomic Landscape of this Rearrangement

摘要

Myxoid/Round Cell Liposarcoma (MRCL) is characterized as a soft tissue sarcoma that is associated with unusual patterns of metastasis to extrapulmonary sites, such as bones and other soft tissue sites. Here, we present a case of a 48-year-old male patient, diagnosed with MRCL. The patient presented with a grade 1 myxoid liposarcoma in his left leg. DNA FISH analysis showed variant rearrangements of the EWSRI (22q12) gene and loss of the 5’ DDIT3 (CHOP 12q13) gene. The variant rearrangement showed one or two fusions with multiple separated (rearranged) signals. The EWSRI-DDIT3 rearrangement has been reported in MRCL. The variant rearrangements of the EWSRI (22q12) gene findings correlate with concurrent conventional cytogenetic findings and were described as nuc ish(EWSR1x2) (5’EWSR1 sep 3’EWSR1x1)128/100,(5’EWSR1,3’EWSR1)x1~3(5’EWSR1 con 3’EWSR1x1~2)57/100. The variant rearrangements of the DDIT3 (CHOP 12q13) gene findings were described as nuc ish(5’DDIT3x1,3’DDIT3x2)(5’DDIT3 con 3’DDIT3x1)195/200. Molecular cytogenetic studies also showed a rearrangement of EWSRI (22q12) in 64 of nuclei and variant rearrangement in 31.5 of nuclei. A loss of DDIT3’s (12q13) 5’ signal was found in 97.5 of interphase nuclei. Molecular pathology results indicated the patient was positive for EWSRI (exon 7) and DDIT3 (exon 2) fusion. The patient underwent radiation therapy pre-resection of the myxoid liposarcoma. The most common form of MRCL is associated with t(12;16)(q13;p11), leading to FUS-CHOP and EWS-CHOP fusion proteins acting as aberrant transcription factors. The key element here is that this EWSRI-DDIT3 rearrangement led to a translocation t(12;22)(q13;q12) which is a rare cytogenetic event that led to the development of MRCL in this patient.