Adult liver rhabdomyosarcoma complicated with sarcomatoid carcinoma: A case report

BACKGROUND Rhabdomyosarcoma (RMS) is a type of malignant tumor originating from rhabdomyocytes or mesenchymal cells differentiating into rhabdomyocytes. Hepatic pleomorphic RMS is a rare malignant liver tumor. Hepatic sarcomatoid carcinoma is also a rare epithelial malignant tumor originating from the liver; it is characterized by the coexistence of both carcinomatous and sarcomatoid spindle cell components. CASE SUMMARY This paper reports a special case of an elderly woman whose initial liver puncture biopsy showed pleomorphic RMS. After chemotherapy with the vincristine + doxorubicin + cyclophosphamide regimen, the alpha-fetoprotein level increased significantly. Therefore, a second liver puncture was performed, the pathological result of which was hepatic sarcomatoid carcinoma. Next-generation sequencing revealed MET gene amplification with an average copy number of 9 in the tumor tissue; however, both fluorescence in situ hybridization and immunohistochemical tests were negative for MET amplification. The treatment regimen was adjusted to chemotherapy combined with immunotherapy; however, the disease progressed rapidly, and the overall survival was only 6 months. CONCLUSION By sharing the diagnosis and treatment process of this patient and reviewing the relevant literature, we aim to help clinicians enhance their understanding of two rare diseases, namely pleomorphic RMS and sarcomatoid carcinoma of the liver.