原发性皮肤SMARCA4缺陷型未分化恶性肿瘤(SD-UMN)是一种罕见且最近描述的实体,其特征在于SMARCA4(BRG1)蛋白表达的丧失,参与染色质重塑。SD-UMN由于其稀有性和独特的组织病理学和免疫组织化学特征而提出了诊断挑战。在这份报告中,我们介绍了一例原发性皮肤SD-UMN的67岁男性,溃烂,右脸颊有结节出血.组织病理学检查显示高细胞真皮肿瘤,由多形性上皮样细胞组成,具有明显的有丝分裂和坏死,缺乏任何分化的形态学证据。免疫组织化学分析显示SMARCA4和SMARCA2表达完全丧失,而INI-1表达保持完整。p53弥漫性表达,p16完全不存在。此外,一系列标记,包括高分子量的细胞角蛋白,p63,SOX10,INSM1,MCPyV,NKX2.2,CD99,CDX2,CD56,ERG,螺母,desmin,雄激素受体,嗜铬粒蛋白,CD34和CD43均为阴性。迄今为止,文献中仅报道了2例原发性皮肤SMARCA4缺陷型未分化肿瘤.因此,该病例报告增加了对该新实体的临床和组织病理学特征的有限知识。该报告强调了在未分化皮肤肿瘤的鉴别诊断中考虑SD-UMN的重要性。
Primary cutaneous SMARCA4-deficient undifferentiated malignant neoplasm (SD-UMN) is a rare and recently described entity characterized by the loss of expression of the SMARCA4 (BRG1) protein, which is involved in chromatin remodeling. SD-UMN presents a diagnostic challenge due to its rarity and unique histopathological and immunohistochemical features. In this report, we present a
case of primary cutaneous SD-UMN in a 67-year-old man who presented with a rapidly growing, ulcerated, and bleeding nodule on his right cheek. Histopathological examination revealed a highly cellular dermal tumor consisting of pleomorphic epithelioid cells with prominent mitotic figures and necrosis, lacking any morphological evidence of differentiation. Immunohistochemical analysis showed a complete loss of SMARCA4 and SMARCA2 expression, while INI-1 expression remained intact. p53 was diffusely expressed, and p16 was completely absent. In addition, a range of markers, including high-molecular-weight cytokeratin, p63, SOX10, INSM1, MCPyV, NKX2.2, CD99, CDX2, CD56, ERG, NUT, desmin, androgen receptor, chromogranin, CD34, and CD43 were all negative. To date, only two cases of primary cutaneous SMARCA4-deficient undifferentiated tumors have been reported in the literature. Therefore, this
case report adds to the limited body of knowledge on the clinical and histopathological features of this novel entity. The report highlights the importance of considering SD-UMN in the differential diagnosis of undifferentiated cutaneous tumors.