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The paucity of evidence-based data regarding the management of ASB tumors is still a major limit of the discipline of ASB surgery, resulting from the rarity and high degree of heterogeneity of these tumors. Therefore, no guidelines exist and prospective large cohort collaborative studies are required in order to consolidate our knowledge of the behavior of each histology encountered, and to assess the clinical and quality-of-life outcomes of the different treatment modalities currently used.The inclusion of systemic therapy in the multimodal approach of locally advanced sinonasal cancers, at least in some selected histologies, may improve locoregional control and reduce the frequency of distant metastasis, allowing longer survival. Response to induction chemotherapy is a strong prognostic factor for a patient's outcome and it may improve disease control by surgery and radiation. Concurrent chemoradiation aims at increasing locoregional control in squamous cell cancer of the head and neck; this is particularly important in sinonasal cancers, with a risk of local relapse of about 30%. Selected histologies may benefit from specific drug combinations, according to varying chemosensitivity. Intestinal-type adenocarcinoma carrying a functional p53 protein may be treated with preoperative cisplatin, 5-fluorouracil, and leucovorin. CT7001 order Sinonasal undifferentiated carcinoma is a chemosensitive disease, where the multimodal approach is necessary to counterbalance the severe prognosis. Sinonasal neuroendocrine carcinoma and olfactory neuroblastoma may benefit from systemic treatments, but their added value has not been so clearly defined yet. Multimodality trials are ongoing to test the activity of induction chemotherapy followed by locoregional curative treatment. A deeper knowledge of the molecular deregulations of these diseases could help in identifying targeted therapies.Particle therapy is a comparatively new radiotherapy treatment form allowing the application of extremely conformal treatment plans. In head and neck malignancies, especially in the paranasal sinus and anterior skull base, this technology is very valuable in order to maintain normal tissue tolerance of critical structures while still applying high doses to the tumour. The following paper will further explore the rationale of particle therapy and available clinical experience of the most commonly treated malignancies arising in these anatomical sites. The potential of particle therapy for re-irradiation in tumours of the paranasal sinus and anterior skull base will also be summarised.Anterior skull base tumors represent a challenge for radiation therapy (RT) planning given the close proximity of the target lesion to numerous critical structures in this complex anatomic location. Despite this challenge, surgery followed by postoperative RT is a common treatment paradigm for malignant sinonasal tumors that has been associated with improved outcomes compared to single-modality treatment. Therefore, technological advancements allowing for increasingly conformal target coverage and sparing of organs at risk are important to accomplish the goal of delivering RT with the highest therapeutic ratio possible. Such advances include both intensity-modulated RT and volumetric-modulated arc therapy, which allow RT to be delivered more precisely than ever before. link2 Furthermore, stereotactic radiosurgery can deliver highly conformal doses of external beam RT in a single or limited number of fractions for the definitive or postoperative management of benign lesions of the anterior base of the skull. These sophisticated photon-based RT strategies have allowed for exciting advances in the contemporary treatment of anterior skull base tumors that will continue to improve patient outcomes and reduce toxicity for years to come.Sinonasal adenoid cystic carcinoma is a rare malignancy characterized by an insidious growth pattern and a tendency for perineural spread along major and minor nerves, resulting in invasion of the skull base and intracranial extension. Therefore, many patients present with advanced disease and involvement of critical structures, making treatment difficult and potentially associated with high morbidity. Surgery represents the mainstay of treatment of the primary tumor. Complete resection of the tumor with negative margins, whenever feasible, is associated with better survival outcomes. However, in the case of extensive involvement of vital structures (e.g., carotid artery, cavernous sinus, optic nerve, Meckel's cave) or when radical surgery could seriously affect the patient's quality of life, a function-preserving subtotal removal of the tumor followed by irradiation can be proposed. The role of surgery is limited to a biopsy in unresectable lesions that are more suitable for non-surgical treatments (e.g., exclusive chemoradiation). Given the difficulty in obtaining negative margins and the propensity for submucosal and perineural spread, adjuvant radiotherapy is strongly recommended. Recently, heavy-particle radiotherapy using protons or carbon ions has emerged as a promising treatment with improved local control. Local failures (60%) and distant metastases (40%) are common and can occur even decades after definitive treatment. The 5-year overall survival ranges from 55 to 70% and it exceeds that of other sinonasal malignancies, but dramatically drops down at 10 years (40%) and further decreases at 20 years (15%). Therefore, a prolonged follow-up of at least 15 years, and possibly lifelong, is mandatory.Sinonasal malignant mucosal melanoma (SNMM) is a rare, aggressive, and capricious tumour accounting for 4% of sinonasal malignancies. Recent studies suggest an increasing frequency. There are few large published series, but all authors report poor outcomes irrespective of treatment of approximately 25% 5-year survival. As a consequence, the American Joint Committee on Cancer (AJCC) have restaged all SNMMs as T3 or greater, irrespective of extent. Surgery remains the principle treatment modality. Survival and recurrence data analysis from a single-centre prospective cohort of 125 cases (all treated surgically with or without radiotherapy) showed 5-year overall survival was 28% and disease-free survival was 23.7%. Local control was achieved for a median of 21 months, with a 5-year disease control rate of 27.7%. However, endoscopically resected cases showed a significant overall survival advantage up to 5 years, confirming that endoscopic resection of SNMM does not adversely affect outcome and may even be beneficial up to 5 years. These findings are supported by other recent series in the literature. Radiotherapy did not improve local control or survival in this study, though there is debate in the literature as to its value. Cervical metastases confer a dramatically worse outcome. Chemotherapy has not previously shown much advantage, but more recently immunologic manipulation with drugs such as ipilimumab have shown promise. Thus far, the mutation status does not appear to affect survival outcomes, but NRAS mutations are relatively frequent and could be targeted in this disease by MEK inhibitors in the future.Sinonasal malignancies are uncommon, representing 1% of all neoplasms. A wide spectrum of malignant neoplasms arise from the sinonasal and skull base regions; the majority of these tumors are poorly or undifferentiated tumors manifesting overlapping features that result in diagnostic challenges. Sinonasal neuroendocrine carcinoma (SNEC) and sinonasal undifferentiated carcinoma (SNUC) are types of sinonasal neuroendocrine tumor, together with olfactory neuroblastoma. They share overlapping clinical, radiological, and histopathological features, albeit with variability in behavior and prognosis between each other. The literature is at variance regarding the appropriate management strategy of these tumors due to their rarity and difficulty in establishing the correct diagnosis. In recent years progress has been made in the diagnostic techniques and treatment strategies implemented for these tumors. Here we provide a comprehensive review of the recent literature, focusing on the recent advances in histopathological and ancillary diagnosis, and different treatment options for SNEC and SNUC.The anterior skull base can be divided into three segments a midline and two symmetrically placed segments located laterally. The midline segment is the roof of the nasal cavity and serves as a watershed between the sinonasal tract and the intracranial space, whereas the lateral segments separate the intracranial compartment from the orbital content. Several peculiar anatomical areas make up the midline segment (posterior frontal plate, cribriform plate, ethmoidal roof, planum sphenoidale, and tuberculum sellae), while the lateral segments are more regular, formed by flat laminae (orbital plates of the frontal bones and lesser wings of the sphenoid). Here we detail each segment of the anterior skull base, emphasizing major landmarks, providing classifications and measurements of key areas, and cautioning the endoscopist about areas to avoid or minimize the occurrence of cerebrospinal fluid leaks, as well as providing recommendations and tips. Several endoscopic and sectional macroscopic anatomical images provide the reader with an informative, illustrative, and broad perspective of anterior skull base anatomy.Nowadays, surgeons have a wide armamentarium of surgical approaches available to safely treat sinonasal malignancies, which includes open approaches, with the traditional craniofacial resection (CFR), and endoscopic transnasal techniques. The correct choice depends on the features of the pathology. It is well known that endoscopic approaches have a lower morbidity compared with traditional open techniques, due to a shorter hospitalization, absence of facial incisions, and avoidance of brain retraction. Moreover, endoscopic surgery presents clear technical advantages. link3 For example, magnification of the surgical field allows the surgeon to carefully identify tumor margins, the site of origin, and the anatomical structures involved by the lesion. Nevertheless, a purely endoscopic approach cannot always provide successful resection of the tumor; the patient must be informed about the possibility of switching to a combined cranioendoscopic resection or CRF, depending on the effective extension of the disease evaluated intraoperatively. Despite these advantages, postoperative complications can occur after endoscopic endonasal surgery, as in any surgical intervention; however, complications after these procedures are less severe and less frequent compared with traditional open approaches. The most common complications observed include skull base reconstruction failure, intraoperative vascular lesions, and orbital or central nervous system complications. Thus, endoscopic endonasal resection, when properly planned and performed by experienced surgeons, is an acceptable treatment for well-selected skull base malignancies with long-term outcomes comparable to those achieved with traditional external approaches.Anterior skull base (ASB) tumors can be classified into three groups according to their site of origin (1) sinonasal neoplasms involving or extending through the anterior cranial base; (2) neoplasms which arise from the bony framework of the base itself; (3) neoplasms originating from adjacent intracranial structures. With few exceptions, most of these tumors have a non-specific appearance on CT and MRI, which limits the role of imaging in terms of characterization. However, treatment planning (transnasal endoscopic surgery in particular) mostly depends upon the tumor map, exploiting the potential of modern cross-sectional imaging. As a result, the radiologist who has to evaluate a neoplasm involving the ASB needs to be fully aware of all the technical solutions available and the specific strengths/weaknesses of the different imaging techniques. Knowledge of radiological anatomy (and its variants) is also essential, which includes the ability to translate the CT appearance of structures into the equivalent MR signal (and vice versa).