UNASSIGNED: Sinonasal inverted papilloma is a rare benign tumor of the nasal cavity and paranasal sinuses (PNS). Radiological evaluation is the key to management.
UNASSIGNED: A 46-year-old male presented with complaints of right nasal congestion and occasional bleeding for 4 months. During anterior rhinoscopy, a pinkish fleshy mass occupying the right nasal cavity was seen. X-ray and computed tomography (CT) PNS view showed opacification in the right nasal cavity and maxillary sinus. An MRI of the nose and PNS revealed a peculiar convoluted striated/cerebriform pattern. Histopathology report described the features of an inverted papilloma. The patient underwent endoscopic removal of the mass under general anesthesia. Surgical resection of the tumor was performed along with adjacent normal mucosal tissues. The patient recovered well and was followed-up for recurrence.
UNASSIGNED: Sinonasal inverted papilloma is commonly found in males in their fifth to sixth decade of life. A CT scan is the initial modality of choice to evaluate the extent of the disease. MRI is superior to CT in distinguishing tumors from other conditions as well as to evaluate soft tissue extensions. Involvement of the frontal sinus is a risk factor for recurrence. The first option for treating an inverted papilloma is complete surgical removal with the adjacent uninvolved mucosa.
UNASSIGNED: In a biopsy-proven case, radiological assessments like CT and MRI play a pivotal role in studying the typical morphology, delineating the extension, and detecting recurrence.

Malignant conversion of sinonasal inverted papilloma (SNIP) occurs in approximately ten percent of cases. These tumors are classically described as locally destructive, but without metastatic potential. Only four cases of malignant conversion with cervical nodal metastases have been described in the English literature. We present the rare case of a 61-year-old Caucasian male with a nasopharyngeal recurrence of malignant SNIP with cervical and retropharyngeal nodal metastases. The patient underwent endoscopic transpterygoid with nasoseptal flap reconstruction, followed by staged bilateral and retropharyngeal node dissection. Histopathology of the specimens demonstrated poorly differentiated invasive nonkeratinizing squamous cell carcinoma with inverted-type features. Three months after surgery, the patient suffered from C1-C2 fractures consistent with osteoradionecrosis and expired. Although the rate of malignant conversion of SNIP is low, this case highlights the need for aggressive, definitive treatment and surveillance.

Inverted sinonasal papilloma (ISP) is a benign epithelial neoplasm arising from the Schneiderian membrane. We report a case of ISP in a 50-year-old male that clinically presented as a polypoid mass in the nasal cavity. Imaging studies revealed it to be an aggressive lesion showing intracranial extension. On histopathological examination of the excised specimen, a diagnosis of ISP was arrived at. However, an extensive sampling of the tissue revealed no evidence of any malignant transformation. Taking into account the suggested viral aetiology for such lesions and the aggressiveness observed in this case, human papillomavirus (HPV) profiling was done but it turned out to be negative. Only one other case of inverted sinonasal papilloma arising from the nasal cavity and involving the brain has been reported in the literature to date. Considering the alarming clinical course in spite of its benign nature, it is important for the pathologist and surgeon to be well informed about this lesion.

Inverted papilloma is a benign epithelial growth in the underlying stroma of the nasal cavity and paranasal sinuses. The pathogenesis of this lesion remains unclear although allergy, chronic sinusitis and viral infections have been suggested as possible causes. The tumor is well known for its invasiveness, tendency to recur and association with malignancy. Recurrence rates of inverted papilloma are unacceptably high, which actually represents residual disease in most cases. In this study, we have presented a case report and reviewed the histological features of sinonasal inverted papilloma.