BackgroundNon-intestinal adenocarcinoma of the nasal cavity and paranasal sinuses (non-ITAC) is a heterogeneous tumour that has rarely been reported in previous studies. We compared and analysed the symptoms, radiographic and pathological features, treatment methods, and prognosis of patients with low-grade (G1) and high-grade (G3) tumours.MethodsThis was a retrospective study included 22 patients with pathologically confirmed non-ITAC of the nasal cavity and paranasal sinuses who were treated between January 2008 and December 2021 at a single centre. Of these, 11 patients had G1 tumours, and 11 patients had G3 tumours. Clinicopathological features, treatment methods, and survival outcomes were analysed.ResultsThe median follow-up period was 48.5 months. Nasal congestion was the most common initial symptom, and the nasal cavity was the most frequently involved site. For G1 tumours, the main treatment was simple surgery, 1 and 3-year overall survival (OS) rates were 100 and 88.9%, while the 1 and 3-year local control (LC) rates were 100 and 100%, respectively. For G3 tumours, the main treatments were surgery combined with radiotherapy and/or chemotherapy,1 and 3-year OS rates were 72.7 and 72.7%, while the 1 and 3-year LC rates were 100 and 90.91%, respectively. G3 tumours was associated with significantly shorter overall survival than G1 tumours (P = 0.035). Patients with stage III-IV showed shorter overall survival compared to stage I-II patients (P = 0.035).ConclusionsNon-ITAC of the nasal cavity and paranasal sinuses may frequently occur in the nasal cavity. The main treatment modality is surgery, supplemented by radiotherapy and chemotherapy. Pathological grade and tumour stage were poor prognostic factors for the disease.