Abstract
Spindle cell/sclerosing rhabdomyosarcoma (RMS) is an uncommon and aggressive neoplasm, especially in adults. This case details a 35-year-old male with a 4-year history of persistent idiopathic facial pain (PIFP), first misdiagnosed owing to the lack of definitive clinical or radiologic evidence. Advanced imaging ultimately identified a malignant tumor in the infratemporal fossa, which was confirmed as rhabdomyosarcoma through histological examination. Owing to the tumor's inaccessibility, surgical removal was unfeasible, and despite chemotherapy, the cancer advanced, resulting in the patient's death. This example highlights the significance of prompt advanced imaging and interdisciplinary cooperation in detecting uncommon cancers that manifest as persistent pain. Given the diagnostic challenge, this case underscores the critical need to consider rhabdomyosarcoma in the differential diagnosis of persistent head and neck pain, especially when conventional evaluations fail to determine a cause. Early recognition and comprehensive diagnostic approaches can improve patient outcomes.