Department of Tumor and Diagnostic Pathology, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki City, Nagasaki, 852-8523, Japan.
Department of Pathology, National Hospital Organization Nagasaki Medical Center, Omura, 856-8562, Nagasaki, Japan.
Diagn Pathol. 2020 Jan 31;15(1):7. doi: 10.1186/s13000-020-0925-y.
Cutaneous pilomatrical carcinosarcoma (CS) is a very rare biphasic tumor composed of admixed epithelial and mesenchymal malignant cells, with limited information on its pathogenesis. We report a case of pilomatrical CS of the scalp with comparative immunohistochemical and molecular analysis together with a review of the literature.
A 74-year-old woman presented with a rapidly growing long-standing tumor of the scalp. The tumor was surgically resected. Histologically, the tumor was 25 mm in diameter, and was composed of carcinoma showing a clear pilomatrical differentiation and sarcoma with pleomorphic spindle cells and giant cells. Both epithelial and mesenchymal components shared focal cytoplasmic and/or nuclear accumulation of β-catenin based on immunohistochemical analysis, although a mutation of exon 3 of the CTNNB1 gene was not detected. Fluorescence in situ hybridization analysis revealed gains of chromosomes 9p21, 3, and 7 in both the epithelial and sarcomatous components.
The current case demonstrated characteristic findings of pilomatricoma and further evidence of partial clonality between the carcinomatous and sarcomatous component, suggesting the possibility of malignant transformation of pilomatricoma. Rapid growth of a pilomatrical tumor should warrant the development of a malignant tumor, including CS.
皮肤毛母质癌肉瘤（CS）是一种非常罕见的双相肿瘤，由混合的上皮和间叶恶性细胞组成，其发病机制的信息有限。我们报告了一例头皮毛母质 CS 的病例，进行了比较免疫组织化学和分子分析，并进行了文献复习。
一位 74 岁女性因头皮长期快速生长的肿瘤就诊。肿瘤行手术切除。组织学上，肿瘤直径 25mm，由具有明显毛母质分化的癌和具有多形性梭形细胞和巨细胞的肉瘤组成。上皮和间叶成分的免疫组织化学分析均显示 β-连环蛋白的细胞质和/或核内有局灶性聚集，尽管未检测到 CTNNB1 基因外显子 3 的突变。荧光原位杂交分析显示上皮和肉瘤成分均存在染色体 9p21、3 和 7 的获得。
本病例表现出毛母质瘤的特征性表现，并且癌性和肉瘤性成分之间存在部分克隆性的进一步证据，提示毛母质瘤发生恶性转化的可能性。毛母质瘤的快速生长应警惕恶性肿瘤的发生，包括 CS。
