Trejo-Scorza Ezequiel, Viña-Ramírez María Isabel, Oviedo-Ayala Norma, Hernández-Faraco Alipio Antonio, Alvarado-Sanavria Jesús María, Paz-Ivanov Simón
Servicio de Cirugía Pediátrica, Maternidad Concepción Palacios y Cátedra de Anatomía Normal, Escuela de Medicina Luis Razetti, Facultad de Medicina, Universidad Central de Venezuela.
Invest Clin. 2007 Dec;48(4):515-27.
We report the case of a male newborn infant with a pedunculated dermic tumor, located in the right malar region; who underwent a complete surgical resection of the tumor and had a satisfactory postoperative evolution. The histopathologic findings disclosed a subcutaneous tumor with a nodular aspect and a subendothelial intravascular growth, constituted by a dual population of small cells and spindle-shaped cells, distributed in a biphasic pattern. All tumor cells showed a strong pericellular reaction for PAS. The immunohistochemical studies revealed: diffuse cytoplasmic positivity for CD34 and Vimentin in all tumor cells, and only spindle-shaped tumor cells and less differentiated isolated neoplastic cells, presented cytoplasmic positivity for the smooth muscle alpha-actin. The electronic microscopy demonstrated a layer of basal membrane and in the citoplasm, numerous intermediate filaments with focal condensations. Based on all these findings, we conclude that this is a myofibroma, a "true hemangiopericytoma" with myofibroblastic differentiation. For this reason, we propose the term myofibropericytoma, in order to highlight its pericytic origin and its myofibroblastic differentiation. We emphasize the need to recognize this entity, in view of its low frequency and the possibility of a diagnostic mistake with other soft tissues tumors that display haemangiopericytoma-like features.
我们报告一例男性新生儿病例，其右颊部有一个带蒂的皮肤肿瘤；该患儿接受了肿瘤的完整手术切除，术后恢复情况良好。组织病理学检查发现一个皮下肿瘤，呈结节状外观，有内皮细胞下血管内生长，由小细胞和梭形细胞的双细胞群组成，呈双相分布。所有肿瘤细胞对PAS均显示强烈的细胞周围反应。免疫组织化学研究显示：所有肿瘤细胞中CD34和波形蛋白呈弥漫性细胞质阳性，只有梭形肿瘤细胞和分化较差的孤立性肿瘤细胞平滑肌α-肌动蛋白呈细胞质阳性。电子显微镜显示有一层基底膜，在细胞质中有许多有局灶性聚集的中间丝。基于所有这些发现，我们得出结论，这是一种肌纤维瘤，一种具有肌纤维母细胞分化的“真性血管外皮细胞瘤”。因此，我们提出“肌纤维血管外皮瘤”这一术语，以突出其周细胞起源及其肌纤维母细胞分化。鉴于其发病率低以及与其他表现出血管外皮瘤样特征的软组织肿瘤存在诊断错误的可能性，我们强调认识这一实体的必要性。
