Shah, Ahmed

Myoepithelial tumors are typically characterized by distinct molecular profiles that have been shown to correlate with their anatomical locations. EWSR1 or FUS rearrangements are common in cutaneous, soft tissue and bone tumors, whereas salivary gland myoepithelial tumors are frequently associated with PLAG1 and HMGA2 alterations. This apparent molecular divergence led some previous studies to doubt a common pathogenetic relationship between myoepithelial tumors of soft tissue and bone with their salivary gland counterparts. Herein, we present primary intraosseous myoepithelioma harboring HMGA2::WIF1 fusion. This fusion has been previously identified in a range of salivary gland myoepithelial tumors including myoepitheliomas, myoepithelial carcinomas arising from pleomorphic adenomas, and pleomorphic adenomas themselves. Primary myoepithelial tumors of the bone are exceedingly rare, and to our knowledge, HMGA2 rearrangements have not been previously reported in soft tissue or bone myoepithelial neoplasms. Through this report, we aim to enhance the existing literature on myoepithelial neoplasms, while highlighting the importance of recognizing primary bone myoepitheliomas and contributing to a broader understanding of the pathogenetic landscape of myoepithelial tumors across diverse tissue types.

The emergence of pathologist-driven molecular reflex testing for tumoural biomarkers is a significant advancement in cancer diagnostics, facilitating targeted cancer therapy for our patients. Based on our experience, the Canadian landscape of pathologist-driven reflex biomarker testing for melanoma lacks standardization and is plagued by a lack of awareness by pathologists and clinicians. This paper comprehensively examines the approaches to reflex biomarker testing for melanoma patients across Canada, highlighting the regional variations in the criteria for initiating molecular testing, the biomarkers tested, and the molecular techniques employed. We also discuss the clinical relevance of biomarkers, emphasizing their alignment with the National Comprehensive Cancer Network ® (NCCN ® ) Clinical Practice Guidelines in Oncology (NCCN Guidelines ® ) as well as ancillary tests such as BRAF VE1 immunohistochemistry to detect BRAF V600E mutation and molecular techniques such as real-time polymerase chain reaction, matrix-assisted laser desorption ionization-time of flight mass spectrometry and next-generation sequencing. Our proposed standardized minimum criteria for reflex testing prioritize melanomas with Breslow thickness >4 mm or disseminated disease, who will most benefit from enhanced delivery of biomarkers and expedited access to targeted therapies while attempting to balance cost-effectiveness and utilization of public healthcare resources with patient outcomes.