Introduction  Biphenotypic sinonasal sarcoma (BSNS) is a recently found entity that first described by Lewis et al. It was then added to the 4th edition of the World Health Organization (WHO) of head and neck tumors in 2012. BSNS has been described as a rare low-grade sarcoma arising in the upper sinonasal tract. It is believed that in the past, BSNS was, likely, previously diagnosed as other low-grade or benign malignancies. Fibrosarcoma, leiomyosarcoma, and peripheral nerve sheath tumors, all fall within the differential diagnosis of BSNS. However, BSNS is unlike other mesenchymal sinonasal tumors, as it displays both neural and myogenic differentiation. BSNS has thus far been recognized in only a hand full of case reports, all of which have reported similar morphologic features of a low-grade soft tissue tumor with neural involvement arising from the nasal cavity or ethmoid air cells in middle aged individuals. In fact, being low-grade sarcoma became such a hallmark characteristic of this tumor that it even received the name low-grade sinonasal sarcoma with neural and myogenic features or LGSSNMF. Case Presentation  We present, however, for the first time, a high-grade differentiation of BSNS in an otherwise healthy 72-year-old female. The patient was referred from an outside ENT (ear, nose, and throat) after pathology from a presumed polypectomy returned positive for a BSNS. Initial imaging revealed erosion through the bilateral lamina papyracea, anterior cranial fossa floor, and posterior table of the frontal sinus. She then underwent a combined endoscopic and bicoronal open approach for resection of the skull base lesion that was found to encompass the entirety of the sinonasal cavities bilaterally. Postoperatively, the patient underwent significant complications including infection of the pericranial flap, pneumocephalus, and eventually death. Discussion  As BSNS is a fairly new entity, currently there has only been four case series conducted, each identifying features of a low-grade sarcoma with both myogenic and neural differentiation. Histologically, BSNS has monophasic spindle cells with uniform, elongated nuclei with scant cytoplasm between benign proliferations of surface-type respiratory epithelium, with a low mitotic rate. Our case, however, revealed pleomorphic hyperchromatic cells with high mitotic activity and necrosis with invasion of bone, staging it as high grade. Immunohistochemistry also differed from the previously reported standards. This case describes a new category for BSNS which may change the differential diagnosis, management, and surgical recommendations that are currently utilized for this skull base neoplasm.

Sinonasal tumors are an uncommon pathological entity and applying the optimal treatment may represent a challenge, even for experienced physicians. A various number of techniques and materials may be used in the reconstruction of craniofacial defects following surgery for extensive sinonasal cancer. The aim of the present study was to present the case of a 33-year-old male patient diagnosed with a large sinonasal tumor and discuss the challenges faced while selecting the most suitable rehabilitation technique. In the present case, it was decided that the optimal solution was to use a craniofacial prosthesis in order to cover the entire defect, as well as a temporoparietal flap. In summary, reconstructive interventions must always be adapted to each individual patient and a multimodal approach may lead to a highly satisfactory outcome, for both the patient and the surgical team. All the reconstructive solutions available must always be kept in mind and adapted to the individual requirements of each case, taking into consideration both the extent of the tumor and the comorbidities of the patient, as there is no one solution that is considered as optimal for all patients.

UNASSIGNED: We report a case of an intraosseous cavernous hemangioma originating from the middle turbinate that expanded into the anterior skull base, without traversing the cribriform plate.
UNASSIGNED: The mass was found incidentally after a computed tomography head was ordered for unrelated reasons. On questioning, the patient denied any nasal symptoms. Magnetic resonance imaging showed an enhancing mass and the radiological imaging supported a broad differential.
UNASSIGNED: The lesion was removed by endoscopic image-guided surgery, and the pathology was that of a benign intraosseous cavernous hemangioma. There was no residual hemangioma on postoperative imaging and the nasal mucosa healed well. This is the first report of an intraosseous cavernous hemangioma of the middle turbinate showing superior expansion to the anterior skull base.
UNASSIGNED: This case demonstrates the extent to which cavernous hemangiomas may expand into surrounding tissues. While these lesions are uncommon, they can be considered as part of a broad differential diagnosis of sinonasal tumors.

Juvenile nasopharyngeal angiofibroma (JNA) is a locally aggressive tumor that predominantly affects adolescent males. Surgical resection is generally considered the standard treatment for both primary and recurrent tumors, regardless of staging. The natural history of these tumors, particularly when untreated or in the setting of residual tumor, is not well characterized. In this article, we report a case of true spontaneous JNA involution. Although the involution of residual tumor after surgical resection has previously been reported, to our knowledge, this is the first documented case of spontaneous JNA involution following a period of tumor growth post-treatment. Laryngoscope, 131:1455-1457, 2021.

Chondromyxoid fibroma (CMF) is a rare, benign neoplasm of the chondroid, myxoid, and fibrous tissue. It characteristically affects the lower extremity long bones, although it may rarely arise within the craniofacial skeleton. We report the diagnosis and management of a 31-year-old male with a large, incidentally discovered CMF originating from the sphenoid sinus. A subsequent review of the literature reveals the need to differentiate from more aggressive neoplasms, such as chondrosarcoma and chondroma, which share radiographic features. A histopathologic examination is crucial for proper diagnosis and treatment. We discuss clinical sequelae, highlight the importance of a thorough pre-operative evaluation, and summarize previously suggested treatment paradigms.

BACKGROUND: Recurrent respiratory papillomatosis is a chronic disease of viral origin affecting the larynx, trachea, and lower airways. Inverted papilloma, most commonly originating from the lateral nasal wall, is typically a single, expansile, locally aggressive tumor that remodels bone around the site of origin.
METHODS: We report a case of histopathologically proven inverted papilloma occurring in a 50-year-old Caucasian man with recurrent respiratory papillomatosis affecting his nasal cavity, larynx, and trachea. This constitutes the first report of nasal involvement in recurrent respiratory papillomatosis. Viral in situ hybridization studies demonstrated evidence of human papillomavirus in both the septum and middle turbinate subsites. Repeat nasal excision with margin analysis is planned.
CONCLUSIONS: This report emphasizes the importance of considering a broad differential diagnosis in patients with papillomata, and obtaining comprehensive histopathologic evaluation of lesions in multiple subsites in order to rule out inverted papilloma or overt malignant transformation, particularly if high-risk human papillomavirus (HPV) subtypes are identified.
METHODS: 4.

Olfactory neuroblastoma (ONB, also called esthesioneuroblastoma) is a rare malignant tumor of neuroectodermal olfactory cells. We report a case of an undifferentiated ONB with unfavorable histology arising ectopically in the nasopharynx. The patient was a 15-year-old male who presented with a right-sided painful neck mass, nasal obstruction, and weight loss. Awareness of the ectopic ONBs, although exceedingly rare, is important when considering differential diagnoses of sinonasal tumors as treatment and prognosis may differ from other lesions.

Case-control studies on malignant sinonasal tumors and occupational risk factors are generally weakened by non-occupational confounders and the selection of suitable controls. This study aimed to confirm the association between sinonasal malignant tumors and patients\' occupations with consideration for sinonasal inverted papillomas (SNIPs) as a control group. Thirty-two patients affected by adenocarcinoma (ADC) and 21 non-adenocarcinoma epithelial tumors (NAETs) were compared to 65 patients diagnosed with SNIPs. All patients were recruited in the same clinical setting between 2004 and 2016. A questionnaire was used to collect information on non-occupational factors (age, sex, smoking, allergies, and chronic sinusitis) and occupations (wood- and leather-related occupations, textile industry, metal working). Odds ratios (OR) with 95% confidence intervals (CI) associated with selected occupations were obtained by a multinomial and exact logistic regression. Between the three groups of patients, SNIP patients were significantly younger than ADC patients (p = 0.026). The risk of NAET increased in woodworkers (OR = 9.42; CI = 1.94⁻45.6) and metal workers (OR = 5.65; CI = 1.12⁻28.6). The risk of ADC increased in wood (OR = 86.3; CI = 15.2⁻488) and leather workers (OR = 119.4; CI = 11.3⁻1258). On the exact logistic regression, the OR associated to the textile industry was 9.32 (95%CI = 1.10⁻Inf) for ADC, and 7.21 (95%CI = 0.55⁻Inf) for NAET. Comparing sinonasal malignant tumors with controls recruited from the same clinical setting allowed demonstrating an increased risk associated with multiple occupations. Well-matched samples of cases and controls reduced the confounding bias and increased the strength of the association.

Basaloid squamous cell carcinoma (BSCC) is a rare variant of squamous cell carcinoma (SCC), which is highly aggressive, with a tendency for multifocality, local invasion, and with a high metastatic potential. Less than forty cases of BSCC of the sinonasal tract have been reported in the literature, and no reports were found on sinonasal BSCC arising from the ethmoid sinus. We report the case of a 78-year-old man who presented with BSCC arising from the ethmoid sinus with extensive bone destruction and intracranial extension. He was treated with craniofacial resection followed by adjuvant intensity-modulated radiation therapy to the tumor bed (60 Gy in 30 fractions), and the upper neck lymph nodes (50 Gy in 25 fractions). At the patient\'s last follow-up, four months after diagnosis, there was no evidence of disease. Aggressive management using craniofacial resection followed by adjuvant radiation therapy with or without radiosensitizing chemotherapy seems to be a reasonable approach to this challenging disease.

We report the first case of hepatoid adenocarcinoma of the skull base, as well as the first reported case in the head and neck region. Hepatoid adenocarcinoma is a rare, aggressive, extrahepatic malignancy with a distinct morphological similarity to hepatocellular carcinoma, in the absence of primary hepatic disease. A 45-year-old man presented with sinus headaches and retro-orbital pain and was found to have a nasopharyngeal mass on endoscopy and a large, destructive sinonasal mass extending intracranially on imaging. Histo- and cytopathological features were similar to hepatocellular carcinoma, and the cells were immunoreactive for α-fetoprotein, epithelial membrane antigen, periodic acid-Schiff, cytokeratin (CK)8/18, CK19, and S100.