Aiki Minako, Yoshimura Hitoshi, Ohba Seigo, Kimura Sotai, Imamura Yoshiaki, Sano Kazuo
Senior Resident, Division of Dentistry and Oral Surgery, Department of Sensory and Locomotor Medicine, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.
Lecturer, Division of Dentistry and Oral Surgery, Department of Sensory and Locomotor Medicine, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.
J Oral Maxillofac Surg. 2014 Jan;72(1):99-105. doi: 10.1016/j.joms.2013.06.212. Epub 2013 Aug 12.
Myofibroma is a rare benign tumor of myofibroblasts that rarely exhibits rapid enlargement and is misinterpreted as a malignant lesion. The aim of this study was to investigate its growth potential and to evaluate the usefulness of preoperative immunohistochemical study for an accurate diagnosis.
A case of rapidly growing myofibroma of the lower gingiva was analyzed using 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography fused with computed tomography (PET/CT) and immunohistochemical study of Ki-67 and p53. The English-language literature from 1981 to 2012 also was reviewed.
An 18F-FDG PET/CT image displayed a high accumulation (maximum standardized uptake value, 14.1) in the lesion. A biopsy specimen showed mitotic activity of spindle-shaped cells, but atypia was not present. The MIB-1 labeling index was 10%, and the p53 test result was negative. The preoperative diagnosis of benign tumor of smooth muscle origin was made from the histopathologic and immunohistochemical features. In a review of 94 cases, tumors involved the mandible (33%), gingiva (23%), tongue (15%), cheek or buccal mucosa (12%), palate (8%), lip (4%), and other areas (5%). Nine cases (9.6%) were described as rapidly enlarging, and 8 cases (8.5%) were suspected of malignancy at initial diagnosis. The preoperative biopsy with immunohistochemical study established an accurate diagnosis in 83% of myofibromas, and no recurrences were reported in these patients.
Careful diagnosis is necessary because these lesions sometimes present clinical and radiologic features that resemble those of malignant tumors. Preoperative immunohistochemical analysis should be performed to avoid misdiagnosis or unnecessary aggressive therapy.
肌纤维瘤是一种罕见的肌成纤维细胞良性肿瘤，极少出现快速增大，常被误诊为恶性病变。本研究旨在探讨其生长潜能，并评估术前免疫组化研究对准确诊断的实用性。
对1例下牙龈快速生长的肌纤维瘤进行分析，采用18F-氟脱氧葡萄糖（18F-FDG）正电子发射断层扫描融合计算机断层扫描（PET/CT）以及Ki-67和p53的免疫组化研究。同时回顾了1981年至2012年的英文文献。
18F-FDG PET/CT图像显示病变处有高摄取（最大标准化摄取值，14.1）。活检标本显示梭形细胞有丝分裂活性，但无异型性。MIB-1标记指数为10%，p53检测结果为阴性。根据组织病理学和免疫组化特征，术前诊断为平滑肌来源的良性肿瘤。在对94例病例的回顾中，肿瘤累及下颌骨（33%）、牙龈（23%）、舌（15%）、颊部或颊黏膜（12%）、腭部（8%）、唇部（4%）及其他部位（5%）。9例（9.6%）被描述为快速增大，8例（8.5%）在初始诊断时被怀疑为恶性。术前活检及免疫组化研究在83%的肌纤维瘤中确立了准确诊断，这些患者均未报告复发。
由于这些病变有时呈现出与恶性肿瘤相似的临床和放射学特征，因此需要仔细诊断。应进行术前免疫组化分析以避免误诊或不必要的积极治疗。
