Lymphatic drainage of sinonasal malignancies and the role of sentinel node biopsies

Abstract Background: Locoregional recurrence is a critical factor in the prognosis of sinonasal malignancies. Due to the rarity of these tumours, as well as the heterogeneity of histologies and anatomical subsites, there is little evidence regarding the rate and location of regional metastases in sinonasal malignancies. Elective regional lymph node dissection in the therapy of sinonasal malignancies has become controversial. On the one hand, elective regional lymph node dissection is considered to be an overtreatment in the cN0 cases. On the other hand, undetected occult lymphatic metastases are associated with a poor prognosis. In this study, we discuss the role of lymph node scintigraphy as a minimally invasive procedure in the treatment of sinonasal malignancies based on our two years of practical experience and the currently available data. Results: This is a descriptive, monocentric, retrospective study, including 20 cases of cN0 malignant sinonasal neoplasm, that underwent a surgical therapy between 2020 and 2022. The following aspects were investigated: tumour entity, localisation of the primary tumour, tumoral stage, localisation of the sentinel lymph nodes, and postoperative complications. Squamous cell carcinoma was the most frequently diagnosed tumour entity (50%), followed by adenocarcinoma (20%) and malignant melanoma (15%), adenoid cystic carcinoma and mucoepidermoid carcinoma. Sentinel lymph nodes were most frequently found in the ipsilateral neck region I (45%), followed by the ipsilateral neck region II (40%). In all cases, the removed lymph nodes were free of malignancy. There were no postoperative complications due to lymph node biopsy. There were no recurrences during the study period. Conclusion: Sentinel node biopsy adds more safety to the management of cN0 sinonasal malignancies due to its low morbidity. Elective neck dissection can be avoided in these cases.