xRead - Nasal Obstruction (September 2024) Full Articles

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ICAR SINONASAL TUMORS

phic adenoma has a predominant epithelial component, little stroma, and no capsule compared to major salivary gland counterparts. 994 On IHC, they can stain positive for cytokeratin, vimentin, S100 protein, smooth muscle actin, and glial fibrillary acidic protein. 994 En bloc resection is recommended. EEA or endoscopic assisted approach provides superior visualization with low recurrence rate. 994,995 Piecemeal resection and paranasal sinus site of origin may result in higher rate of recurrence. 995 Lifelong surveillance is recom mended due to potential for recurrence and malignant transformation. 992 D Phosphaturic mesenchymal tumors Phosphaturic mesenchymal tumors (PMTs) are rare low grade polymorphous tumors that generally affect adults over the fourth decade with no gender predominance. 997 A total of 5%–32% of PMTs arise in the head and neck, and up to 50% occur in the sinonasal tract. 998 The ethmoid sinus is most commonly involved. 998 PMTs commonly cause tumor-induced osteomalacia (TIO), a fibroblast growth factor-23 (FGF-23)-mediated paraneoplastic syndrome that results in bone demineral ization, hyperphosphaturia, and hypophosphatemia. 997,998 Patients are asymptomatic or may present with osteo porosis, pathologic fractures, muscle weakness, or nasal obstruction secondary to mass effect. 997,999 Diagnosis is often delayed due to insidious, nonspecific symptoms and challenges in localizing the lesion. Laboratory evalua tion may show (1) elevated FGF-23, parathyroid hormone, and alkaline phosphatase; (2) normal calcium and vita min D; and (3) low phosphate. 997,998 Rarely, tumors are biochemically inactive. 999 CT may show an enhancing soft tissue lesion with bone erosion; MRI will show diffuse enhancement on T1. PMTs are FDG avid on PET. 997 Technechium-99m octreotide scan may help with localization of TIO associated tumors. 998 PMTs display hemangiopericytoma (HPC)-like vascula ture and adipose tissue. 997,1000,1001 IHC helps differentiate from other lesions; PMTs are usually positive for CD56, ERG, and SATB2. 1000,1001 Surgical resection with wide margins can normalize lab oratory values within 1–7 days and resolve TIO symptoms within months. 997,998 Endoscopic resection has compara ble results to open surgery. 998 Postoperative RT can be used for the rare malignant lesion or for locally invasive dis ease in vital structures. 999,1002 Laboratory values should be monitored due to recurrence risk. For inoperable tumors, phosphorus supplementation can control symptoms. 998

Monoclonal antibody treatment (burosumab) has been reported, but requires further study. 998,1003

E Solitary fibrous tumor HPC is a vascular neoplasm, now classified as a solitary fibrous tumor (SFT), originating from mesenchymal cells with pericyte differentiation. 17 For the purposes of this section, the term HPC will be used in place of SFT. A total of 15%–25% occur in the head and neck, compris ing 1% of all vascular tumors and 2.5% of all vascular sinonasal tumors. 1004–1006 Sinonasal HPC occurs equally in females and males and typically present in the third to fifth decade of life with no identified risk factors. Grossly, HPC is a vascular, firm, circumscribed mass with variable color. 1004 Two systematic reviews reported epistaxis and nasal obstruction as the most common pre senting symptoms. 1007,1008 Bone pain and myopathy from associated hypophosphatemic osteomalacia have been described, with one study noting these symptoms in 4.6% of patients. 1008 HPCs often originate from the ethmoid sinus, nasal sep tum, and inferior and middle turbinates. 1008 On contrast enhanced imaging, they enhance strongly. A characteristic “soap bubble” or “honeycomb” appearance may be present on CT, while typical MRI characteristics are hypointense T1 signal, hyperintense T2 signal, and avid enhancement with intratumoral flow voids. 19,1009 HPC stains intensely positive for vimentin and focally positive for CD34. While most HPCs are benign, malignancy can occur. Necro sis, cellular pleomorphism, moderate/high cellularity, and mitotic rate of > 4 mitoses/2 mm 2 are features associated with malignant conversion. 1010–1012 Surgical resection is the primary treatment modality for HPC, and complete resection is the most impor tant prognostic factor. Systematic reviews by Dahodwala et al. ( n = 104) and Duval et al. ( n = 190) found that 98% of patients underwent surgical resection, while < 2% underwent RT. 1007,1008 Half of the patients underwent open surgical approaches (most commonly rhinotomy) ( n = 100), but 97% of cases have been performed endoscop ically since 2003 ( n = 82). 1007 Factors such as involvement of the anterior/inferolateral maxillary, anterior frontal sinus, or extrasinus extension limited a purely endoscopic approach. 1013 There was no significant difference between open versus endoscopic approach with respect to recur rence rates or time to recurrence, but there was a trend toward better outcomes with the endoscopic approach. Preoperative embolization was reported in 8.6% of cases and assisted in optimizing the environment for an endo scopic approach ( n = 10). 1007