纤维软骨性脂肪瘤6例临床病理学分析

Fibrocartilaginous lipoma:a clinicopathological analysis of six cases

目的探讨由纤维软骨、纤维及脂肪构成的纤维软骨性脂肪瘤的临床病理学特征、免疫表型、分子遗传学改变及鉴别诊断。方法回顾性分析佛山市中医院、复旦大学附属肿瘤医院、郑州大学附属第五医院、哈尔滨医科大学附属第四医院4家医院病理科2017年1月至2022年2月存档的6例纤维软骨性脂肪瘤,对其临床病理特征、免疫表型、诊断、鉴别诊断及预后进行分析。结果6例病例中,男性3例,女性3例,年龄36~69岁,中位年龄53岁。肿瘤发生在四肢、头颈部和躯干,表现为局部缓慢性生长的无痛性肿块,境界清楚,位于皮下或深部软组织内。大体检查,3例有完整的纤维包膜,1例无包膜但境界清楚,2例周边附少许横纹肌组织,肿瘤由灰黄色脂肪组织和混杂的灰白色区域组成,平均直径2.9 cm(1.5~5.5 cm);镜下观察,瘤组织主要由不同比例的成熟脂肪、纤维及纤维软骨组织构成。纤维软骨呈结节状或片块状,其内可见脂肪细胞;瘤细胞形态温和,未见核分裂象。免疫组织化学显示瘤组织内纤维软骨细胞表达S-100蛋白及SOX9,脂肪细胞表达S-100蛋白、Adipopholin及HMGA2,梭形成纤维细胞表达CD34,但不表达平滑肌肌动蛋白和结蛋白,RB1蛋白表达无缺失,4例暂未发现分子遗传学异常。随访10~51个月,5例无复发,1例仅行活检。结论纤维软骨性脂肪瘤是一种良性的脂肪肿瘤,含有纤维软骨、纤维及脂肪成分。免疫组织化学表达脂肪及软骨标志物,暂未发现特异性分子遗传学改变,熟悉其临床病理学特征有助于与具有相似形态的间叶性肿瘤相鉴别。

Objective To investigate the clinicopathological characteristics,immunophenotype,molecular genetics and differential diagnoses of fibrocartilaginous lipomas which consist of adipose tissue,fibrocartilage and fibrous elements.Methods The clinicopathological features,immunohistochemical profiles and molecular profiles in six cases of fibrocartilaginous lipomas diagnosed at Foshan Traditional Chinese Medicine Hospital,Fudan University Shanghai Cancer Center,the Fifth Affiliated Hospital of Zhengzhou University and the Fourth Affiliated Hospital of Harbin Medical University from January 2017 to February 2022 were included.The follow-up information,diagnosis and differential diagnoses were evaluated.Results There were three males and three females with a median age of 53 years(range 36-69 years)at presentation.Tumors were located in the extremities,the head and neck region and trunk;and presented as painless masses that were located in the subcutaneous tissue or deep soft tissue.Grossly,three cases were well defined with thin capsule,one case was well circumscribed without capsule,two cases were surrounded by some skeletal muscle.The tumors were composed of fatty tissue with intermingled gray-white area.The tumors ranged from 1.50-5.50 cm(mean 2.92 cm).Microscopically,the hallmark of these lesions was the complex admixture of mature adipocytes,fibrocartilage and fibrous element in varying proportions;the fibrocartilage arranged in a nodular,sheet pattern with some adipocytes inside.Tumor cells had a bland appearance without mitotic activity.Immunohistochemical analysis using antibodies to SMA,desmin,S-100,SOX9,HMGA2,RB1,CD34,adipopholin was performed in six cases;the fibrocartilage was positive for S-100 and SOX9,adipocytes were positive for S-100,adipopholin and HMGA2;CD34 was expressed in the fibroblastic cells,while desmin and SMA were negative.Loss of nuclear RB1 expression was not observed.Other genetic abnormalities had not been found yet in four cases.Follow-up information was available in six cases;there was no recurrence in five,and one patient only underwent biopsy of the mass.Conclusions Fibrocartilaginous lipoma is a benign lipomatous tumor with mature adipocytes,fibrocartilage and fibrous elements.By immunohistochemistry,they show the expression of fat and cartilage markers.No specific molecular genetics changes have been identified so far.Familiarity with its clinicopathological features helps the distinction from its morphologic mimics.