Successful Sequential Multimodal Therapy for Lingual Rhabdomyosarcoma in a Young Adult: Case Report.

Lingual rhabdomyosarcoma (RMS) in adults is an exceedingly rare malignancy, with very few cases reported and no standardized treatment guidelines. We present the case of a 19-year-old male diagnosed with lingual RMS who underwent sequential multimodal therapy. The patient initially received doxorubicin combined with ifosfamide chemotherapy followed by cisplatin combined with 5-fluorouracil, both of which resulted in disease progression. A third-line regimen with vincristine, actinomycin D, and cyclophosphamide (VAC) together with pembrolizumab achieved only transient stabilization and was limited by toxicity. Subsequent treatment with cetuximab together with bevacizumab induced a significant partial response with acceptable tolerance, which was consolidated with intensity-modulated radiotherapy (IMRT) to the primary site and cervical lymph nodes. Surveillance imaging confirmed durable locoregional control without evidence of systemic disease, whereas swallowing and phonation were preserved. This case illustrates the value of individualized stepwise management in adult RMS and suggests that the integration of immunotherapy and antiangiogenic therapy may provide meaningful tumor control and functional preservation in selected patients.