Surgical treatment for uncommon malignancies of the paranasal sinuses and anterior cranial fossa: report of two cases and literature review.

Malignant tumors of the nasal and paranasal cavities account for only 3-5% of all head and neck neoplasms. Among these tumors, rare instances of human papillomavirus (HPV)-positive multiphenotypic carcinomas and biphenotypic sarcomas have been documented. Two such cases are reported here, along with the respective treatment approaches. The first involved a 39-year-old male patient diagnosed with HPV-positive multiphenotypic carcinoma. Surgical treatment was performed through a craniofacial and transfacial approach, en bloc resection, and reconstruction of the anterior cranial base with a fascia lata graft and pericranial flap. The second involved a 41-year-old female patient diagnosed with biphenotypic sarcoma. Surgical treatment was performed through centripetal endoscopic tumour resection. In both cases, adjuvant radiotherapy was performed after obtaining the histopathological result and negative margins. Both patients were free of disease during postoperative follow-up. Given the rarity of these cases, there are no established guidelines outlining specific treatments. It is recommended that such tumours are assessed in interdisciplinary committees to determine the optimal treatment options. Typically, this will involve surgical resection via craniofacial and transfacial approaches or endoscopic surgery, depending on the diagnosis, extent of anatomical involvement, and tumour aggressiveness. Additionally, the potential benefits of adjuvant radiotherapy should be evaluated, as it has demonstrated promising outcomes, even in cases with positive margins.