Magro Gaetano, Greco Paolo, Alaggio Rita, Gangemi Pietro, Ninfo Vito
Dipartimento GF Ingrassia, Policlinico Universitario G Rodolico, Anatomia Patologica, Università di Catania, Catania, Italy.
Pathol Res Pract. 2008;204(11):837-43. doi: 10.1016/j.prp.2008.05.007. Epub 2008 Jul 24.
We report on a previously unrecognized fibro-myofibroblastic tumor in the oral cavity of a 15-year-old girl. Morphologically, the tumor mimicked a rhabdomyosarcoma, botryoid variant. It was composed of mitotically active small- to medium-sized, vimentin+/desmin+, round- to oval- to epithelioid-shaped cells embedded in an alternating fibrous to myxoid/edematous stroma. These cells were separated from the overlying squamous epithelium by a rim of fibrous stroma. The tumor contained abundant small- to medium-sized, thin-walled blood vessels without hyalinization. Frequently, neoplastic cells condensed around these vessels. An unusual and striking feature was the presence of numerous hyalinized collagen mats, including "amianthoid-like fibers", similar to those observed in myofibroblastomas. The presence of these collagen mats and the expression of desmin, in association with no immunoreactivity to myogenin and MyoD1, were in keeping with the fibro-myofibroblastic nature of the tumor, excluding the diagnosis of embryonal rhabdomyosarcoma. Regarding fibro-myofibroblastic tumors, we believe that the present case falls within the wide spectrum of benign stromal tumors, originally described in the lower female genital tract, but potentially occurring also at extragenital sites. As morphological and immunohistochemical features were reminiscent of, but not identical with, angiomyofibroblastoma, the term "polypoid angiomyofibroblastoma-like tumor" is proposed. Awareness and recognition of this tumor is crucial to avoid a diagnosis of malignancy.
我们报告了一名15岁女孩口腔中一种此前未被认识的纤维-肌纤维母细胞瘤。形态学上，该肿瘤酷似葡萄状横纹肌肉瘤。它由有丝分裂活跃的小到中等大小、波形蛋白阳性/结蛋白阳性、圆形到椭圆形再到上皮样的细胞组成，这些细胞嵌入交替的纤维性到黏液样/水肿性的间质中。这些细胞通过一层纤维性间质与上方的鳞状上皮分隔开。肿瘤含有丰富的小到中等大小、薄壁的血管，无玻璃样变性。肿瘤细胞常围绕这些血管聚集。一个不寻常且显著的特征是存在大量玻璃样变性的胶原垫，包括“石棉样纤维”，类似于在肌纤维母细胞瘤中观察到的那些。这些胶原垫的存在以及结蛋白的表达，同时对肌生成素和MyoD1无免疫反应，符合肿瘤的纤维-肌纤维母细胞性质，排除了胚胎性横纹肌肉瘤的诊断。关于纤维-肌纤维母细胞瘤，我们认为本病例属于广泛的良性间质肿瘤范畴，最初在女性下生殖道描述，但也可能发生于生殖器外部位。由于形态学和免疫组化特征让人联想到血管肌纤维母细胞瘤，但又不完全相同，故提出“息肉样血管肌纤维母细胞瘤样肿瘤”这一术语。认识和识别这种肿瘤对于避免误诊为恶性肿瘤至关重要。
