xRead - Nasal Obstruction (September 2024) Full Articles

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sis. Should progression to MM occur, systemic therapy will then be indicated with a possible role for bone marrow transplantation. Population-based studies have reported generally favorable outcomes, with 5- and 10-year out comes greater than 80%, 1884 and pooled systematic reviews have reported somewhat lower survival rates (71.8% at median 39 months follow-up). 1861 METASTATIC TUMORS Metastases of extranasal malignant tumors to the sinonasal region are extremely rare, with fewer than 200 cases described in the literature since 1947. Due to its low occurrence rate, the data hereby have been acquired by retrospective case reports and small case series. Similar to primary sinonasal tumors, the presenting symptoms of sinonasal metastases are nonspecific and determined by the involved sinonasal site and primary tumor pathology. Metastases tend to be quite vascular, and the most com mon presenting sign is epistaxis. Metastases originating from the nasal cavity and maxillary sinus often present with nasal obstruction, rhinorrhea, facial pain, and numb ness, whereas headache, visual impairment, proptosis, and diplopia are more common with sphenoid sinus and orbital involvement. Skull base or cavernous sinus exten sion can result in cranial nerve dysfunction and visual alterations. Sometimes, the patient will experience symp toms related to the primary disease (e.g., shortness of breath for lung cancer). 1908,1909 The most common metastatic tumor affecting the sinonasal region is renal cell carcinoma (RCC), which accounts for 50% of cases. However, most primary tumors can result in sinonasal metastases, and the most fre quently reported are lung, breast, gastrointestinal tract, liver, urogenital, thyroid, and skin malignancies. Rarely are sinonasal metastases derived from an unknown ori gin. Primary sinonasal tumors and local extension of a primary tumor involving the oral cavity, orbit, and intracra nial cavity should also be considered. The maxillary sinus is involved in 36%–50% of cases, followed by the sphenoid, ethmoid, and frontal sinuses and nasal cavity. 159,1910–1914 A very small number of cases of metastasis to the nasal tip and septum have been reported. 1915 Mean age and risk fac tors for patients with sinonasal metastases vary depending on the primary tumor pathology. Sinonasal involvement can be synchronous with the primary presentation but can also present more than a decade after the original tumor is diagnosed. Generally, since metastatic disease indicates an advanced stage of the primary disease, the prognosis is grim at the point of presentation and is often associated with poor QOL and mortality. However, early detection and diagnosis, coupled with aggressive treat XXVII

ment, may improve sinonasal symptoms and, in selected cases, prolong survival. 1910–1912 Hematogenous, lymphatic, and direct spread of tumor have been postulated as the source for sinonasal metas tases. Intravasation of tumor cells from the primary site into blood vessels and through the vertebral valveless low-pressure venous plexus (Batson plexus), which com municates among the deep pelvic veins, intercostal, vena cava, and the azygos system, may allow tumor cells to disseminate from the caval system through the valveless epidural space and into the sinonasal region in a retro grade fashion. 1908,1916 Additionally, tumor cells might also travel through the arterial circulation into the head and neck system in an anterograde fashion. The rich blood sup ply of the maxillary sinus may explain its higher metastases frequency. Lymphatic dissemination might occur when cells spread in a retrograde fashion from regional lymph nodes through the thoracic duct, the intercostal, medi astinal, or supraclavicular lymph vessels to the sinonasal region. 1912,1917 Another suggested pathway is directly from an adjacent site, such as transcribriform spread from a meningeal lesion. 1918 Initial evaluation is similar to the workup of a pri mary sinonasal tumor workup and includes a thorough history, a physical examination that includes endoscopy, and an assessment of the oral cavity, neck, and cranial nerves (including visual acuity and fields). As with any sinonasal neoplasm, imaging studies should be obtained prior to biopsy to appreciate the nasal anatomy, tumor epicenter and extent, vascularity, and appropriate surgi cal approach. There are no known radiographic findings specific to metastases. A CT with contrast can demon strate bony erosion and remodeling, enhancement and vascularity, orbital, foramina, and skull base invasion, and overall, the tumor aggressiveness. MRI can show soft tissue involvement, tumor vascularity, neurovascular, lep tomeningeal, and mucosal spread. A tissue biopsy should be obtained to establish the diagnosis. Once confirmed as metastatic disease, appropriate evaluation within a mul tidisciplinary team is required. Whole-body staging scans (e.g., PET/CT) might also be required for complete pri mary tumor anatomical localization, evaluation for other metastatic spread, and staging assessment. For patients with a known history of malignancy, lab studies includ ing complete metabolic panels, which may indicate a specific extranasal origin (e.g., hyponatremia related to RCC) or a paraneoplastic syndrome, urinalysis, and spe cific biomarkers such as carcinoembryonic antigen (CEA) and prostate-specific antigen (PSA) may be useful as part of the workup. 1910,1919,1920 Several factors should be taken into account when tailoring a patient- and disease-specific treatment strat egy. Significant prognostic factors include the biological