Rhabdomyosarcoma of the Middle Ear and Mastoid in Children: Experience of the Beijing Children's Hospital—BCH

Objectives To conduct a retrospective analysis of the clinical characteristics and prognosis of rhabdomyosarcoma of the middle ear and mastoid (MERMS) in children. Methods Treatment and outcome of 37 children with MERMS from Beijing Children's Hospital (July 2016–April 2023) were evaluated. Results The median age of this cohort was 54 months. Initially, 9 children were misdiagnosed with otitis media and/or granulomas, whereas 11 underwent anti-infective therapy. The disease manifested with a high level of local aggressiveness (T2; 83.8%), often accompanied by meningeal invasion (MI; 27 of 37), encompassing cranial base bone erosion (CBBE; 27 of 27), intracranial extension (ICE; 14 of 27), and cranial nerve paralysis (CNP; 22 of 27), with a predominance of facial nerve involvement in CNP cases. The primary treatment modality for this region was a combination of radiation and chemotherapy. The early response to neoadjuvant chemotherapy emerged as a prognostic factor, significantly impacting 5-year event-free survival (EFS) and overall survival (OS): complete response (CR), 85.7 and 100%; partial response (PR), 43.7 and 65.2%; and progressive disease/stable disease (PD/SD), 16.7 and 16.7% ( p = 0.019 and 0.001, respectively). A total of 13 patients passed away, with 4 fatalities attributed to the dissemination of tumor cells in the cerebrospinal fluid and 9 resulting from intracranial progression that impacted the central nervous system. The 5-year OS and EFS were (67.1 ± 7.8%) and (51.1 ± 9.1%), respectively. Conclusion MERMS is a highly aggressive malignancy with complex clinical manifestations and frequent cranial nerve involvement. Early recognition, aggressive multimodal treatment, and close monitoring for treatment response are crucial for improving survival outcomes.