Objective: To investigate the clinical, radiological, histological and molecular features and the differential diagnosis of fibrocartilaginous mesenchymoma (FM). Methods: Four cases of FM diagnosed in the Department of Pathology, the Sixth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine from 2020 to 2022 were analyzed. Related literature was also reviewed. Results: Case 1 was a 10-year-old girl with bone destruction in the sacrum and L5 articular processes revealed by CT scan. Case 2 was a 7-year-old girl with an aggressive lesion in her right distal ulna. Case 3 was an 11-year-old boy with a lesion in the metaphysis of his left proximal tibia. Case 4 was an 11-year-old boy with bone destruction in the distal portion of a radius. Microscopically, the four tumors all consisted of numerous spindle cells, hyaline cartilage nodules, and bone trabeculae. The hypocellular to moderately cellular spindle cell component contained elongated cells with slightly hyperchromatic, mildly atypical nuclei arranged in bundles or intersecting fascicles. Benign-appearing cartilaginous nodules of various sizes and shapes were scattered throughout the tumors. There were areas mimicking epiphyseal growth-plate characterized by chondrocytes arranged in parallel columns and areas of enchondral ossification. The stroma was rich in mucus in case 1. Mutation of GNAS and IDH1/IDH2 and amplification of MDM2 gene were not found in any of the three tested cases. Conclusions: FM is very rare and tends to affect young patients. It most frequently occurs in the metaphysis of long tubular bones, followed by the iliac-pubic bones and vertebrae. FM is characterized by a mixed population of spindle cells, hyaline cartilage nodules and trabeculae of bone, without specific immunophenotypes and molecular alternations. As a borderline, locally aggressive neoplasm, surgical removal with a wide margin is generally the treatment of choice for FM.
目的： 探讨纤维软骨性间叶瘤（fibrocartilaginous mesenchymoma，FM）的临床特点、影像学表现、病理学形态、免疫表型、分子病理特征及鉴别诊断。 方法： 收集上海交通大学医学院附属第六人民医院病理科2020—2022年4例FM的临床及影像学资料，对其病理学形态、免疫表型和分子病理特征进行回顾性分析，并复习相关文献。 结果： 例1为会诊病例，患儿女，10岁。CT示骶骨和L5关节突骨质破坏。例2，患儿女，7岁。右尺骨远段病灶合并病理性骨折。例3，患儿男，11岁。左侧胫骨近端干骺端骨质破坏。例4为会诊病例，患儿男，11岁。左侧桡骨远端干骺端病灶伴骨皮质破坏。镜下肿瘤均由多量的梭形细胞成分、透明软骨结节和小梁状的骨构成。梭形细胞区域细胞密度低至中等，呈束状或交叉排列，梭形细胞轻至中度异型，例1间质富于黏液。透明软骨结节呈骺板软骨样排列。骨小梁周围被覆骨母细胞。例2~4均未发现GNAS、IDH1/IDH2基因突变和MDM2基因扩增。 结论： FM罕见，多位于长骨的干骺端，其次为髂骨、耻骨和脊柱骨；好发于青少年。增生的梭形细胞、透明软骨结节和编织骨的形成是FM三大特征性形态表现，无特异性免疫表型和分子遗传学改变。FM为中间型肿瘤，有局部复发倾向，需与软骨性纤维结构不良、髓内高分化骨肉瘤和去分化软骨肉瘤等鉴别；广泛手术切除为首选治疗方式，预后良好。.