Department of Dermatology and Dermatopathology, Nippon Medical School Musashi Kosugi Hospital.
J Nippon Med Sch. 2021 Jan 8;87(6):355-358. doi: 10.1272/jnms.JNMS.2020_87-609. Epub 2020 Aug 1.
We report a case of solitary infantile myofibroma (IM) with partially CD34-positive neoplastic cells on the back of a newborn boy. Ultrasonography showed a multilocular mass with a hypoechoic center surrounded by an isoechoic rim. Histopathological analysis revealed that the lesion was composed of small, round cells that were tightly packed and uniform. The cells had oval nuclei and were pale, CD34-positive, and richly cellular. They had interlacing fascicles of spindle cells with features of myofibroblasts with α-smooth muscle actin positivity. We speculate that neoplastic cells in most IMs differentiate towards myofibroblasts. However, in rare cases, their differentiation is more primitive and they express CD34, with or without α-smooth muscle actin expression.
我们报告了一例发生于新生儿背部的孤立性婴儿性肌纤维瘤（IM），部分肿瘤细胞 CD34 阳性。超声检查显示多房性肿块，中心呈低回声，周围为等回声边缘。组织病理学分析显示病变由紧密排列、均匀一致的小圆细胞组成。这些细胞具有卵圆形核，胞质淡染，CD34 阳性，细胞丰富。它们交织成束的梭形细胞具有成肌纤维细胞的特征，α-平滑肌肌动蛋白阳性。我们推测大多数 IM 中的肿瘤细胞向成肌纤维细胞分化。然而，在罕见情况下，它们的分化更为原始，表达 CD34，伴有或不伴有 α-平滑肌肌动蛋白表达。
