Inoue Takuya, Sada Asuka, Mori Toru, Misago Noriyuki, Narisawa Yutaka
Division of Dermatology, Department of Internal Medicine, Faculty of Medicine, Saga University, Nabeshima 5-1-1, Saga 849-8501, Japan.
J Cutan Pathol. 2010 Jun;37(6):678-82. doi: 10.1111/j.1600-0560.2009.01302.x. Epub 2009 Mar 30.
Myofibroma is an uncommon benign soft tissue disorder, which is usually congenital or present in early infancy. Myofibroma usually manifests as a single mass. When there are multiple lesions, the term myofibromatosis is used. The characteristic histopathological feature of the myofibroma is the coexistence of two distinct areas. One area mainly contains plump spindle cells with thin blunt-ended nuclei and eosinophilic cytoplasm, thus indicating myoid characteristics. The other area contains either round or polygonal cells with slightly pleomorphic, hyperchromatic nuclei or small spindle cells typically arranged around a distinct hemangiopericytoma-like vascular pattern. In the present case, the majority of the tumor was composed of the plump myoid spindle cells. This led to an initial diagnosis of a piloleiomyoma. However, the tumor cells were not immunohistochemically positive for desmin. Moreover, careful examination revealed a hemangiopericytoma-like vascular pattern characterized by the presence of high cellular areas with irregular vascular spaces. These features led to the final diagnosis of the myofibroma. It is therefore important to recognize the leiomyoma-like variants of myofibromas.
肌纤维瘤是一种罕见的良性软组织疾病，通常为先天性或在婴儿早期出现。肌纤维瘤通常表现为单个肿块。当存在多个病灶时，则使用肌纤维瘤病这一术语。肌纤维瘤的特征性组织病理学特征是两个不同区域并存。一个区域主要包含核呈细钝端、胞质嗜酸性的丰满梭形细胞，显示出肌样特征。另一个区域包含圆形或多边形细胞，核稍具多形性、深染，或小梭形细胞，通常围绕独特的血管外皮细胞瘤样血管模式排列。在本病例中，肿瘤的大部分由丰满的肌样梭形细胞组成。这导致最初诊断为毛发性平滑肌瘤。然而，肿瘤细胞免疫组化desmin呈阴性。此外，仔细检查发现一种血管外皮细胞瘤样血管模式，其特征为存在细胞密集区域及不规则血管间隙。这些特征最终诊断为肌纤维瘤。因此，认识肌纤维瘤的平滑肌瘤样变体很重要。
