**9. Conclusions**

HNOS is a rare and complex disease, for which its treatment approach is still under debate. It shows different clinical and oncologic behavior from OS of the extremities, thus requiring specific studies, which are scarce due to its infrequency. Further population-based studies are required to determine the therapeutic approach that will prove most successful. Surgical resection with large, clear margins remains the mainstay of optimal treatment, and adjuvant treatments should be discussed on a case-by-case basis. For the time being, there is consensus in that it should be managed in tertiary centers that concentrate the cases and that can offer the tools to confirm the correct diagnosis and perform the correct staging, evaluate and offer the possibility of adequate ablative and reconstructive surgery, adjuvant treatment if required, and the correct follow-up.
