Sinonasal giant cell tumour. Report of four cases and review of the literature.

Objective: Sinonasal giant cell tumour (SnGCT) is very rarely reported. The aim of the study is to present a series of SnGCT treated with an endoscopic or combined approach and to carry out a review of the literature on this topic. Methods: This case series encompassed the clinical data of all the SnGCT surgically treated with curative intent at two different referral centres, between 2001 and 2024. The information was extrapolated to report epidemiologic and clinical data, surgical approach and follow up. A comprehensive clinical review of the literature was also carried out. Results: Among 4 patients included, 3 were treated with a pure endoscopic resection and remained disease-free at the last follow up, while one was managed with a combined approach, who is alive with disease. From the review we found only 32 cases of SnGCT reported, mostly treated with an open approach. Local recurrence was documented in 12.5% of cases, while distant metastasis in 3%. Conclusions: SnGTC is a benign but locally aggressive neoplasm that can present as a lytic lesion. The clinical behaviour of GCT is unpredictable, and it tends to recur locally and may even metastasise. In the nose and paranasal sinuses it is an exceedingly rare entity, but should be considered in the differential diagnosis with a large variety of histologies. Surgery is the treatment of choice for resectable lesions.