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Abstract：
BACKGROUND: Primary pulmonary myxoid sarcoma (PPMS) is a rare, low-grade malignant tumor, constituting approximately 0.2% of all lung tumors. Despite its rarity, PPMS possesses distinctive histological features and molecular alterations, notably the presence of EWSR1-CREB1 gene fusion. However, its precise tissue origin remains elusive, posing challenges in clinical diagnosis.
UNASSIGNED: A 20-year-old male patient underwent a routine physical examination 6 months prior, revealing a pulmonary mass. Following surgical excision, microscopic evaluation unveiled predominantly short spindle-shaped tumor cells organized in a fascicular, beam-like, or reticular pattern. The stromal matrix exhibited abundant mucin, accompanied by lymphocytic and plasma cell infiltration, with Russell bodies evident in focal areas. Immunophenotypic profiling revealed positive expression of vimentin and epithelial membrane antigen in tumor cells, whereas smooth muscle actin and S-100, among others, were negative. Ki-67 proliferation index was approximately 5%. Subsequent second-generation sequencing identified the characteristic EWSR1-CREB1 gene fusion. The definitive pathological diagnosis established PPMS. The patient underwent no adjuvant chemotherapy or radiotherapy and remained recurrence-free during a 30-month follow-up period.
CONCLUSIONS: We report a rare case of PPMS located within the left lung lobe interlobar fissure, featuring Russell body formation within the tumor stroma, a novel finding in PPMS. Furthermore, the histomorphological characteristics of this case highlight the diagnostic challenge it poses, as it may mimic inflammatory myofibroblastic tumor, extraskeletal myxoid chondrosarcoma, or hemangiopericytoma-like fibrous histiocytoma. Therefore, accurate diagnosis necessitates an integrated approach involving morphological, immunohistochemical, and molecular analyses.
UNASSIGNED: A 20-year-old male patient underwent a routine physical examination 6 months prior, revealing a pulmonary mass. Following surgical excision, microscopic evaluation unveiled predominantly short spindle-shaped tumor cells organized in a fascicular, beam-like, or reticular pattern. The stromal matrix exhibited abundant mucin, accompanied by lymphocytic and plasma cell infiltration, with Russell bodies evident in focal areas. Immunophenotypic profiling revealed positive expression of vimentin and epithelial membrane antigen in tumor cells, whereas smooth muscle actin and S-100, among others, were negative. Ki-67 proliferation index was approximately 5%. Subsequent second-generation sequencing identified the characteristic EWSR1-CREB1 gene fusion. The definitive pathological diagnosis established PPMS. The patient underwent no adjuvant chemotherapy or radiotherapy and remained recurrence-free during a 30-month follow-up period.
CONCLUSIONS: We report a rare case of PPMS located within the left lung lobe interlobar fissure, featuring Russell body formation within the tumor stroma, a novel finding in PPMS. Furthermore, the histomorphological characteristics of this case highlight the diagnostic challenge it poses, as it may mimic inflammatory myofibroblastic tumor, extraskeletal myxoid chondrosarcoma, or hemangiopericytoma-like fibrous histiocytoma. Therefore, accurate diagnosis necessitates an integrated approach involving morphological, immunohistochemical, and molecular analyses.
摘要：
背景：原发性肺粘液样肉瘤（PPMS）是一种罕见的，低度恶性肿瘤,约占所有肺肿瘤的0.2%。尽管它很罕见,PPMS具有独特的组织学特征和分子改变，特别是EWSR1-CREB1基因融合的存在。然而,其精确的组织起源仍然难以捉摸，给临床诊断带来挑战。
■一名20岁男性患者在6个月前接受了常规体检，显示肺部肿块.手术切除后,微观评估揭示了主要是短纺锤形的肿瘤细胞组织在一个束状，梁状，或网状模式。基质基质显示出丰富的粘蛋白，伴有淋巴细胞和浆细胞浸润，拉塞尔的尸体在重点区域很明显。免疫表型分析显示肿瘤细胞中波形蛋白和上皮膜抗原阳性表达，而平滑肌肌动蛋白和S-100等，是阴性的。Ki-67增殖指数约为5%。随后的第二代测序鉴定了特征性的EWSR1-CREB1基因融合体。明确的病理诊断建立了PPMS。患者未接受辅助化疗或放疗，在30个月的随访期内仍无复发。
结论：我们报告了一例位于左肺叶叶间裂内的罕见PPMS，以肿瘤间质内的罗素身体形成为特征，PPMS中的一个新发现。此外，这个病例的组织形态特征突出了它所带来的诊断挑战，因为它可能模仿炎性肌纤维母细胞瘤，骨外粘液样软骨肉瘤，或血管外皮细胞瘤样纤维组织细胞瘤。因此,准确的诊断需要一种涉及形态学的综合方法，免疫组织化学，和分子分析。
■一名20岁男性患者在6个月前接受了常规体检，显示肺部肿块.手术切除后,微观评估揭示了主要是短纺锤形的肿瘤细胞组织在一个束状，梁状，或网状模式。基质基质显示出丰富的粘蛋白，伴有淋巴细胞和浆细胞浸润，拉塞尔的尸体在重点区域很明显。免疫表型分析显示肿瘤细胞中波形蛋白和上皮膜抗原阳性表达，而平滑肌肌动蛋白和S-100等，是阴性的。Ki-67增殖指数约为5%。随后的第二代测序鉴定了特征性的EWSR1-CREB1基因融合体。明确的病理诊断建立了PPMS。患者未接受辅助化疗或放疗，在30个月的随访期内仍无复发。
结论：我们报告了一例位于左肺叶叶间裂内的罕见PPMS，以肿瘤间质内的罗素身体形成为特征，PPMS中的一个新发现。此外，这个病例的组织形态特征突出了它所带来的诊断挑战，因为它可能模仿炎性肌纤维母细胞瘤，骨外粘液样软骨肉瘤，或血管外皮细胞瘤样纤维组织细胞瘤。因此,准确的诊断需要一种涉及形态学的综合方法，免疫组织化学，和分子分析。
