xRead - Nasal Obstruction (September 2024) Full Articles

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ICAR SINONASAL TUMORS

2 Biphenotypic sinonasal sarcoma Females predominate in BSNS (61%–69%). 1301–1303 Histo logically, BSNS is a cellular, low-grade spindle cell neo plasm with elongated nuclei arranged in a “herringbone” pattern and a low mitotic rate. Many tumors exhibit a potentially distracting respiratory epithelial hyperplasia regarded as entrapment of benign epithelium, under scoring the need for ample biopsy material. Of note, BSNS is not PET avid. 1304 The PAX3::MAML3 fusion gene is commonly associated, although other fusion genes exist. 1305–1307 Tumor cells demonstrate a neural and myo genic phenotype with S100, smooth muscle actin, and muscle-specific actin staining in > 90% of cases; none express SOX10 or cytokeratin, aiding in separation from synovial sarcoma and MPNST. 1301,1302,1308,1309 ß-Catenin is often positive ( > 80% cases) but is not specific[24]. 1432 Bony invasion occurs in 21%–57% of cases. 1301,1302 Surgery is the most common management modality. Local recur rence rates range between 32% and 44%, but OS approaches 100%. 1301,1302 Though tumors may be locally aggressive with > 20% demonstrating orbital or skull base involve ment, no cervical or distant metastases have been iden tified, and only two deaths have been reported. 1308,1310 Adjuvant RT following surgery results in an equivalent recurrence rate of 33.3%, though the margin status of these patients was unknown, undermining the assessment of adjuvant RT influence. 1311 Adjuvant chemotherapy is rarely indicated, except with positive margins or unre sectable disease. 1311 Literature-reported recurrences have occurred within 60 months of treatment. 1309 Importantly, the recent recognition of this distinct histological entity limits the duration of follow-up within the literature and may impact our understanding of long-term survival outcomes. 3 Leiomyosarcoma History of CRT or retinoblastoma increases the risk of leiomyosarcoma. 1312,1313 Leiomyosarcoma demonstrates smooth muscle differentiation and may arise post-RT and concomitantly with other tumors, such as retinoblas toma. Spindled tumor cells label with smooth mus cle actin (SMA), desmin, and/or caldesmon, and S100 expression is absent. RB1 protein loss occurs in 75% of cases. EBV-associated smooth muscle tumors may mimic leiomyosarcoma, but are considered a borderline tumor category, many with a transplantation history and multi focal disease. 1313 Sinonasal leiomyosarcoma is treated with surgery in 93% of cases; 35% of patients receive adjuvant RT and/or chemotherapy. 1312–1315 High-grade leiomyosarcoma

Studies suggest an improved prognosis of these sarcoma subtypes compared to sinonasal rhabdomyosarcoma. 51,1242 The largest study on sinonasal sarcomas included 352 patients with all sarcoma histologies; 50% had “miscella neous” subtypes that include the less common pathologies discussed here. Maxillary sinus tumors exhibited poorer outcomes versus all other sinonasal subsites. Sphenoid sarcoma had the best prognosis; 5-year survival was 63% versus 41% for maxillary sinus tumors—thus postulat ing that maxillary sinus tumors may present at a more advanced stage. 51 However, Martin et al. studied sinonasal sarcoma outcomes using the SEER database and did not corroborate these findings. 1296 Age also affects prognosis. 51 Five-year survival for patients < 10 years old was 63.1%; 54.5% of patients received RT, but this did not improve 5-year survival. 1296 Disease stage significantly predicts OS. 265 Nega tive surgical margins and the absence of metastatic lymphadenopathy significantly improve prognosis for patients with nonrhabdomyosarcoma sinonasal sarcoma. 1236,1297–1299 No significant survival difference has been shown between endoscopic and open surgical resec tion; the approach should be dictated by tumor extent, surgeon expertise, and location. 265 ES, leiomyosarcoma, and MPSNT are associated with improved overall 5-year survival versus other sarcomatous lesions, including fibrosarcoma and synovial sarcoma. 265 Fibrosarcoma Fibrosarcoma presents at a mean age of 54.5 years and affects males and females equally. 49 Once consid ered a common adult sarcoma, refinements in micro scopic criteria and ancillary testing have led fibrosar coma to be regarded as a diagnosis of exclusion, and it is probably exceptionally rare. Histologically, spindle cells are arranged in chevrons, herringbone, or stori form pattern. Bland appearance may contribute to initial benign misdiagnosis. 1300 High mitotic rate and tumor cellularity, as well as male sex, associate with higher mortality risk. 1300 In fibrosarcoma, 64.1% have regional nodal disease. 49 However, among other types of non rhabdomyosarcomatous lesions, the cervical metastatic rate is significantly lower (3%–30%). 265,1296 Fibrosarcoma 5 year DSS is 77.8%; OS is 71.7%, improved from earlier 20th century reports of 21%. 49,1293 Patients treated surgically had significantly improved prognosis versus those treated with RT alone (DSS 33.3% for RT alone). Surgery alone ver sus surgery followed by RT was associated with improved 5-year DSS (87.5% vs. 76.2%), likely due to selection bias. 49 1