Soft tissue tumor with novel NR1D1-MAML1 fusion in a pediatric case.

Virchows Archiv : an international journal of pathology 2020 Dec

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We herein describe soft tissue tumor arising in the lower extremity of a pediatric patient. The tumor displayed a unique and wide range of histological features, sheet-like and cohesive growth pattern consisting of enlarged round to epithelioid atypical cells with a large alveolar and pseudopapillary histological architecture, focally mimicking alveolar soft part sarcoma and MiT family translocation renal cell carcinoma. Tumor cells were focally immunoreactive for cytokeratin, S-100, and EMA. RNA sequencing identified a novel in-frame NR1D1 (exon 5)-MAML1 (exon 2) gene rearrangement resulting in the formation of a putative chimeric protein containing the N-terminal C4-type zing finger domains of NR1D1 and the C-terminal MAML1 protein, which was confirmed by subsequent RT-PCR, Sanger sequencing, and FISH assay. To the best of our knowledge, NR1D1-MAML1 fusion has not yet been described in any neoplasms, suggesting the emergence of a novel tumor entity.

Citation

Masato Komatsu, Nobuyuki Yamamoto, Teruya Kawamoto, Yohei Kawakami, Hitomi Hara, Suguru Uemura, Noriyuki Nishimura, Toshihiro Akisue, Ryosuke Kuroda, Kazumoto Iijima, Naoe Jimbo, Maki Kanzawa, Kazuyoshi Kajimoto, Tomoo Itoh, Takanori Hirose. Soft tissue tumor with novel NR1D1-MAML1 fusion in a pediatric case. Virchows Archiv : an international journal of pathology. 2020 Dec;477(6):891-895