Fadl Amr, Feldman Andrew L
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN.
J Hematop. 2023 Jun;16(2):125-126. doi: 10.1007/s12308-023-00537-8. Epub 2023 Mar 14.
An 18-year-old female presented with a 4.5 cm abdominal mass. Biopsy showed sheet-like growth of large tumor cells with round to oval nuclei, 1-2 nucleoli, and abundant cytoplasm. Immunohistochemistry showed strong, uniform CD30 staining and cytoplasmic ALK staining. B-cell markers (CD20, CD79a, PAX5, kappa/lambda) and T-cell markers (CD2, CD3, CD4, CD5, CD43, granzyme B, T-cell receptor-β) were negative. Other hematopoietic markers (CD45, CD34, CD117, CD56, CD163, EBV) were negative, but CD138 was positive. Non-hematopoietic markers showed desmin positivity and negativity for S100, melan A, HBM45, PAX8, PAX2, WT1, MYO-D1, myogenin, pancytokeratin, and CAM5.2. Sequencing identified fusion. A diagnosis of epithelioid inflammatory myofibroblastic sarcoma (EIMS) was made. EIMS is a rare, aggressive form of inflammatory myofibroblastic tumor typically presenting in children and young adults. The tumor comprises large epithelioid cells that express ALK and often CD30. ALK-positive ALCL has a similar age range and also is a large-cell tumor expressing CD30 and ALK. Other ALK-positive neoplasms (e.g., carcinomas, ALK-positive large B-cell lymphoma, ALK-positive histiocytosis) typically lack CD30 and have distinct clinicopathologic features that aid diagnosis. Hematopathologists need to distinguish EIMS from ALK-positive ALCL, which frequently shows loss of pan-T-cell antigens. Careful morphologic evaluation for the hallmark cells of ALCL and comprehensive phenotyping are critical to avoid this diagnostic pitfall. If known, the rearrangement partner gene may also provide diagnostic clues; for example and occur in EIMS but not ALCL.
一名18岁女性患者，腹部有一个4.5厘米的肿块。活检显示大肿瘤细胞呈片状生长，细胞核圆形至椭圆形，有1 - 2个核仁，细胞质丰富。免疫组化显示CD30染色强且均匀，ALK呈细胞质染色。B细胞标志物（CD20、CD79a、PAX5、kappa/lambda）和T细胞标志物（CD2、CD3、CD4、CD5、CD43、颗粒酶B、T细胞受体-β）均为阴性。其他造血标志物（CD45、CD34、CD117、CD56、CD163、EBV）为阴性，但CD138为阳性。非造血标志物显示结蛋白阳性，而S100、黑素A、HBM45、PAX8、PAX2、WT1、MYO-D1、肌细胞生成素、全细胞角蛋白和CAM5.2为阴性。测序鉴定出 融合。诊断为上皮样炎性肌成纤维细胞肉瘤（EIMS）。EIMS是炎性肌成纤维细胞瘤的一种罕见且侵袭性的形式，通常发生于儿童和年轻人。该肿瘤由表达ALK且常表达CD30的大上皮样细胞组成。ALK阳性的间变性大细胞淋巴瘤（ALCL）有相似的年龄范围，也是一种表达CD30和ALK的大细胞肿瘤。其他ALK阳性肿瘤（如癌、ALK阳性大B细胞淋巴瘤、ALK阳性组织细胞增多症）通常缺乏CD30，且具有有助于诊断的独特临床病理特征。血液病理学家需要将EIMS与ALK阳性的ALCL区分开来，后者常显示泛T细胞抗原缺失。对ALCL的特征性细胞进行仔细的形态学评估和全面的表型分析对于避免这种诊断陷阱至关重要。如果已知，重排伙伴基因也可能提供诊断线索；例如， 和 发生于EIMS而非ALCL。
