Department of Pathology, Brigham and Women's Hospital.
Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
Am J Clin Pathol. 2021 Jul 6;156(2):229-245. doi: 10.1093/ajcp/aqaa223.
The SWI/SNF complex core subunit SMARCB1 is inactivated in a variety of neoplasms that share characteristic "rhabdoid" cytomorphology. The aim of this study was to evaluate SMARCB1-deficient soft tissue neoplasms on cytology to identify diagnostic clues.
Eleven SMARCB1-deficient tumors, including six epithelioid sarcomas, three malignant rhabdoid tumors, one epithelioid malignant peripheral nerve sheath tumor (MPNST), and one poorly differentiated chordoma with fine-needle aspiration (FNA), serous effusion, or touch prep (TP) from two institutions, were included. Targeted next-generation sequencing (NGS) was performed in two cases.
Evaluation of FNA (n = 4), effusion (n = 4), and TP (n = 3) in nine adult and two pediatric patients demonstrated cellular samples (n = 11), epithelioid cells with rhabdoid morphology (n = 9), eccentrically located nuclei with prominent nucleoli (n = 7), and cytoplasmic bodies (n = 4); two patients were diagnosed on FNA with cell block. Immunohistochemistry (IHC) demonstrated SMARCB1 loss in all cases and keratin and/or EMA expression in all but the epithelioid MPNST; NGS identified SMARCB1 inactivation in both cases.
SMARCB1-deficient soft tissue neoplasms comprise a variety of tumors with epithelioid morphology and frequent expression of keratin and/or EMA. Recognition of characteristic rhabdoid morphology on cytology can prompt IHC and/or NGS testing for SMARCB1 deficiency and help establish the diagnosis.
SWI/SNF 复合物核心亚基 SMARCB1 在具有特征性“横纹肌样”形态学的多种肿瘤中失活。本研究旨在评估细胞学上的 SMARCB1 缺陷软组织肿瘤，以确定诊断线索。
包括两家机构的六个上皮样肉瘤、三个恶性横纹肌样肿瘤、一个上皮样恶性外周神经鞘瘤（MPNST）和一个分化差的脊索瘤，共 11 个 SMARCB1 缺陷肿瘤，通过靶向下一代测序（NGS）进行了两个病例的研究。
对来自 9 名成人和 2 名儿科患者的 4 例细针抽吸（FNA）、4 例积液和 3 例触诊制备（TP）的评估显示，细胞样本（n=11）、具有横纹肌样形态的上皮样细胞（n=9）、偏心定位的具有明显核仁的核（n=7）和细胞质体（n=4）；两名患者通过 FNA 进行细胞块诊断。免疫组织化学（IHC）显示所有病例均存在 SMARCB1 缺失，除上皮样 MPNST 外，所有病例均表达角蛋白和/或 EMA；NGS 确定了两种情况下的 SMARCB1 失活。
SMARCB1 缺陷的软组织肿瘤包括具有上皮样形态且频繁表达角蛋白和/或 EMA 的多种肿瘤。在细胞学上识别出特征性横纹肌样形态可以提示进行 IHC 和/或 NGS 检测 SMARCB1 缺陷，并有助于确立诊断。
