Sinonasal teratocarcinosarcoma masquerading as an olfactory neuroblastoma

Sinonasal teratocarcinosarcoma (SNTCS) is a rare malignancy characterized by potent invasiveness, rapid growth, and a poor prognosis. Due to its diverse histopathological morphology, complex components, and insidious growth sites, as well as inadequate biopsies, SNTCS is often misdiagnosed as other tumors, and this misdiagnosis directly affects the treatment and prognosis of patients. Here, we report a case of an elderly SNTCS patient who underwent intranasal endoscopic tumor resection under systemic anesthesia. His preoperative diagnosis and intraoperative frozen sections both led to a misdiagnosis of olfactory neuroblastoma (ONB). However, after surgeries, the patient was diagnosed with SNTCS based on routine histopathology and immunohistochemical staining. He then underwent follow-up but died of tumor recurrence six months later.