Dos Santos Jessica Luana, Ocamoto Eduardo Akira, Almeida Luciana Yamamoto, Teixeira Lucas Ribeiro, Ribeiro-Silva Alfredo, León Jorge Esquiche
*Department of Pathology and Forensic Medicine, Ribeirão Preto Medical School (FMRP/USP), University of São Paulo (USP), Ribeirão Preto †Public Health Service, Jaboticabal ‡Hematology Division, Department of Clinical Medicine, Ribeirão Preto Medical School (FMRP/USP), University of São Paulo (USP), Ribeirão Preto §Oral Pathology, Department of Stomatology, Public Oral Health, and Forensic Dentistry, University of São Paulo, School of Dentistry of Ribeirão Preto (FORP/USP), University of São Paulo, Ribeirão Preto, Brazil.
J Craniofac Surg. 2017 Mar;28(2):e158-e160. doi: 10.1097/SCS.0000000000003348.
Spindle cell lipoma (SCL) and pleomorphic lipoma constitute a spectrum of lipomatous lesions with distinctive clinicopathological features. Multiple variants of SCL have been reported including fibrous, plexiform, vascular, pseudoangiomatous, low-fat/fat-free, and myxoid changes. This paper describes an unusual patient with a 1-cm submucosal nodular lesion excised from the buccal mucosa of a 55-year-old woman with classic histopathological and immunohistochemical features of "low-fat" plexiform SCL with prominent myxoid stroma, which initially suggested a soft-tissue myxomatous lesion other than SCL. The current lesion exhibited microscopically few adipocytes supported by network-like myxoid proliferations with retraction artifacts from the surrounding stromal connective tissue. Immunohistochemistry was positive for vimentin, CD34, CD10, and S100, the latter only on adipocytes. The Ki-67 was <1%. Pan-cytokeratin (AE1/AE3), desmin, alpha-SMA, EMA, bcl-2, p53, and remarkably retinoblastoma protein (pRb) were negative. "Low-fat" plexiform SCL bear no significant prognostic significance, but this lesion may challenge the diagnosis even experienced pathologists.
梭形细胞脂肪瘤（SCL）和多形性脂肪瘤构成了一系列具有独特临床病理特征的脂肪性病变。已报道SCL的多种变体，包括纤维性、丛状、血管性、假血管瘤样、低脂/无脂以及黏液样改变。本文描述了一名不寻常的患者，从一名55岁女性的颊黏膜切除了一个1厘米的黏膜下结节性病变，其具有“低脂”丛状SCL的典型组织病理学和免疫组化特征，伴有显著的黏液样基质，最初提示为SCL以外的软组织黏液瘤性病变。当前病变在显微镜下显示少量脂肪细胞，由网络样黏液样增生支持，并伴有来自周围基质结缔组织的收缩假象。免疫组化结果显示波形蛋白、CD34、CD10和S100呈阳性，后者仅在脂肪细胞上呈阳性。Ki-67小于1%。全细胞角蛋白（AE1/AE3）、结蛋白、α-平滑肌肌动蛋白、上皮膜抗原、bcl-2、p53以及视网膜母细胞瘤蛋白（pRb）均为阴性。“低脂”丛状SCL没有显著的预后意义，但这种病变可能对诊断构成挑战，即使是经验丰富的病理学家也不例外。
