Primary leiomyosarcoma of the lumbar soft tissue treated with multimodal therapy, including anlotinib: A case report.

Leiomyosarcoma (LMS) originating in the deep soft tissue of the lumbar region is rare. Notably, data on the treatment response and clinical outcomes of LMS following multimodal therapy, particularly involving the multitarget tyrosine kinase inhibitor anlotinib, remain limited. The present report describes the case of a 48-year-old man with primary LMS of the lumbar deep soft tissue. Pathological evaluation demonstrated tumor infiltration of skeletal muscle, marked cellular atypia and a Ki-67 proliferation index of 70% in the recurrent mass (second resection specimen). The patient underwent three surgical resections combined with adjuvant chemoradiotherapy; following rapid disease progression after the third operation, anlotinib treatment was initiated. Treatment was temporally associated with a complete response, according to Response Evaluation Criteria in Solid Tumors 1.1 criteria, at 2 months, which was accompanied by extensive clinical tumor necrosis and sloughing. Disease progression occurred after ~6 months, consistent with the development of acquired resistance. The patient died 12 months after starting treatment with anlotinib, with an overall survival time of 36 months from the initial diagnosis. The present case illustrates the potential activity of anlotinib in recurrent LMS and highlights the challenge of acquired resistance, emphasizing the need for molecular profiling and combination strategies to achieve more durable disease control.