Abstract
RATIONALE: Biphenotypic sinonasal sarcoma is a rare malignant tumour exclusively involving the sinonasal cavity. These tumours have variable and atypical presentations. Early approach and correct treatment modalities are key factors in the management of such cases. PATIENT CONCERN: A 48-year-old male patient presented with left-sided nasal obstruction and intermittent nasal bleeding for one year. DIAGNOSIS: Biphenotypic sinonasal sarcoma confirmed on histopathological examination and immunohistochemistry. TREATMENT: The patient underwent surgical excision with left lateral rhinotomy and bifrontal craniotomy with skull base repair. The patient also received postoperative radiotherapy. OUTCOME: The patient is on regular follow-up with no similar complaints. TAKE-AWAY LESSON: Treating team should keep the diagnosis of biphenotypic sinonasal sarcoma in mind while investigating a patient with nasal mass. Surgical management is the treatment of choice, due to its local aggressive nature and proximity to the brain and eyes. Postoperative radiotherapy is vital to prevent tumour recurrence.