Identification of a novel SH3PXD2B::FER fusion in a case of plexiform myofibroblastic tumor and review of the literature.

Fibroblastic/myofibroblastic tumors encompass a wide spectrum of lesions. Among them, plexiform myofibroblastoma (PM) represents a rare and distinctive entity recently described as mostly occurring in children and with a favorable prognosis. Histologically, PM shows SMA, CD34, and desmin expression in most cases, while it is negative for β-catenin and S100.

LMNA::NTRK1 and PRDX1::NTRK1 Atypical Spitz Tumor: A Report of Two Additional Cases With Histological, Immunohistochemical, and Molecular Insights.

Over the past decade, advancements in molecular biology have contributed to changes in the diagnostic classification of Spitz neoplasms, including Spitz nevi, atypical Spitz tumors, and Spitz melanomas. The recent World Health Organization classification of skin tumors identifies fusion kinases, including NTRK1, NTRK2, and NTRK3, as critical drivers of these lesions. New fusion genes have continued to expand the spectrum of known molecular alterations, particularly within the category of Spitz NTRK-rearranged lesions.

Spindle Cell Lesions with Oncogenic EGFR Kinase Domain Aberrations: Expanding the Spectrum of Protein Kinase-Related Mesenchymal Tumors.

EGFR aberrations are reported in a subset of myofibroblastic lesions with kinase domain duplication (EGFR-KDD) and exon 20 mutations being assigned to infantile fibrosarcomas (IFS), mesoblastic nephroma, and fibrous hamartoma of infancy (FHI), respectively. In this retrospective study, we correlated molecular findings with the histomorphology of 14 myofibroblastic lesions harboring such genetic changes identified by NGS. We additionally performed DNA methylation profiling (DNAmp) and immunohistochemistry.