Primary Synovial Sarcoma of the Ethmoid Sinus in a Young Female: A Rare Case Associated With Tuberous Sclerosis Complex.

Synovial sarcoma is a rare and aggressive soft tissue malignancy, with head and neck involvement comprising a small fraction of cases. Ethmoid sinus localization is exceptionally rare, with only a few cases documented in the literature. We present the case of a 34-year-old female who developed progressive right-sided nasal obstruction and epistaxis, with imaging revealing a locally invasive ethmoidal mass. Histopathological and immunohistochemical analysis confirmed a diagnosis of poorly differentiated synovial sarcoma. Incidentally, renal and intracranial findings suggested a possible underlying tuberous sclerosis complex. The patient was managed with a multimodal approach, including neoadjuvant chemotherapy (ifosfamide and doxorubicin), radiotherapy, and endoscopic surgical resection. Postoperative imaging demonstrated complete tumor clearance, and histology confirmed no residual malignancy. This case highlights the diagnostic and therapeutic challenges posed by ethmoidal synovial sarcoma and underscores the importance of individualized, multidisciplinary care, while also presenting an association with tuberous sclerosis that warrants further exploration.