PRRX1-rearranged mesenchymal/fibroblastic tumor is a recently proposed, molecularly defined soft tissue tumor, which has not yet been included in the WHO’s most recent edition of soft tissue tumors. This entity has previously been reported in a wide age range (20-76 years). However, we report the first pediatric case in an 11-year-old patient presenting with 5.5 cm mass in the head and neck region. Our case is also the second reported case of a PRRX1 (exon 1)::NCOA1 (exon 15) fusion transcript to date.
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DermawanJKAzzatoEMJebastin ThangaiahJ, et alPRRX1-NCOA1-rearranged fibroblastic tumour: a clinicopathological, immunohistochemical and molecular genetic study of six cases of a potentially under-recognised, distinctive mesenchymal tumour. Histopathology. 2021;79(6):997-1003. doi:10.1111/his.14454
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ChenCHChangKCChuangCHFuJTHuangHY. The emerging PRRX1-NCOA fibroblastic neoplasm: a combined reappraisal of published tumors and two new cases. Virchows Arch. 2022;481(1):111-116. doi:10.1007/s00428-021-03219-x
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CloutierJMMaloneyNSWangWLLazarAJ. Pigmented PRRX1::NCOA1-rearranged fibroblastic tumor: a rare morphologic variant of an emerging mesenchymal tumor. J Cutan Pathol. 2022;49(9):802-807. doi:10.1111/cup.14262
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WarmkeLMMichalMMartínekP, et al“PRRX1-rearranged mesenchymal tumors”: expanding the immunohistochemical profile and molecular spectrum of a recently described entity with the proposed revision of nomenclature. Virchows Arch. 2023;483(2):207-214. doi:10.1007/s00428-023-03575-w
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CordierFFadaeiSFerdinandeL, et alRevealing RB1 loss in an emerging entity: report of two cases of PRRX1-rearranged mesenchymal tumours. J Clin Pathol. 2025;78(3):154-160. doi:10.1136/jcp-2023-209267
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PulsFAgaimyAFluckeU, et alRecurrent fusions between YAP1 and KMT2A in morphologically distinct neoplasms within the spectrum of low-grade fibromyxoid sarcoma and sclerosing epithelioid fibrosarcoma. Am J Surg Pathol. 2020;44(5):594-606. doi:10.1097/PAS.0000000000001423
SolomonJPLinkovIRosadoA, et alNTRK fusion detection across multiple assays and 33,997 cases: diagnostic implications and pitfalls. Mod Pathol. 2020;33(1):38-46. doi:10.1038/s41379-019-0324-7
