When Appearances Deceive: From Poorly Differentiated Carcinoma to unveiling Olfactory Neuroblastoma in a Highly Vascular Sinonasal tumor.

Sinonasal tumors are an uncommon pathological entity, often presenting with overlapping clinical and radiological features, which makes their diagnosis particularly challenging. Less than 2% of these are vascular tumors, with their diagnoses ranging from benign to malignant conditions. Even with advanced imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI), which provide a near-accurate picture of the extent of the disease, distinguishing them between benign and malignant vascular tumors remains difficult. We present the case of a 42-year-old female who experienced a year-long history of nasal obstruction, severe headache, and intermittent unilateral nasal bleeding. Imaging revealed a highly vascular sinonasal tumor, raising the possibility of benign vascular neoplasms, though malignant tumors were also considered a rare differential. Subsequent surgical excision and frozen section analysis revealed a poorly differentiated sinonasal squamous cell carcinoma. However, postoperative histopathology confirmed the diagnosis of Olfactory Neuroblastoma. The patient underwent combined surgical resection followed by postoperative chemotherapy. This case report highlights the challenges associated with the diagnosis of sinonasal tumors and the significance of histopathological evaluation as the key to unveil the final diagnosis.