Sinonasal teratocarcinosarcoma is an extremely rare, highly malignant neoplasm that frequently invades the surrounding soft tissues, as well as the orbit and cranium, from an early stage. We encountered a case of sinonasal teratocarcinosarcoma that extended into the cranium and present a report of the case here. The patient was a 66-year-old man who presented with an 8-month history of nasal obstruction and anosmia, was examined at the otolaryngology department of a local hospital. The patient was diagnosed as having a nasal cavity tumor and was referred to our department. Examination revealed a milky white mass in left middle meatus. CT and MRI revealed that the tumor was mainly located in the left ethmoidal sinus, but had invaded the nasal cavity, maxillary sinus, sphenoidal sinus, orbit, and cranium. Biopsy findings led to the suspicion of nasal cavity squamous cell carcinoma or olfactory neuroblastoma, but a definitive diagnosis could not be arrived at. PET-CT, revealed accumulation in the primary tumor, with a max SUV of 8, but no evidence of other metastasis. Anterior cranial base surgery was performed and based on the variegated pathological picture of the resected specimen, a diagnosis of teratocarcinosarcoma was made. As the tissue type showed a high degree of malignancy, the patient was treated by surgery followed by postoperative chemoradiotherapy using cisplatin. Survival was confirmed for 3 years 9 months from the onset. A nasal cavity tumor eroding the skull base with a variegated pathological picture should raise the possibility of teratocarcinosarcoma.
