Syed Madiha, Mushtaq Sajid, Loya Asif, Hassan Usman
Department of Histopathology, Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore, Pakistan.
Department of Histopathology, Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore, Pakistan.
Ann Diagn Pathol. 2021 Feb;50:151660. doi: 10.1016/j.anndiagpath.2020.151660. Epub 2020 Nov 5.
Mesenchymal chondrosarcoma is a rare subtype of chondrosarcoma. The tumor has a characteristic bimorphic pattern with areas of poorly differentiated small round cell component and interspersed islands of well differentiated hyaline cartilage. Histological diagnosis of mesenchymal chondrosarcoma is very challenging especially in small biopsies when tumor presents with little cartilaginous component. In such cases, it is very difficult to distinguish mesenchymal chondrosarcoma from other round blue cell tumors like Ewing's sarcoma, rhabdomyosarcoma, small cell osteosarcoma and desmoplastic round blue cell tumor. Immunohistochemically, mesenchymal chondrosarcoma stains positive for NKX2.2, CD99, S100 and SOX9. This immunoprofile is non-specific and overlaps with other round blue cell tumors. Till recently, there was no reliable immunohistochemical marker to differentiate mesenchymal chondrosarcoma from other round blue cell tumors. NKX3.1, though widely used as a diagnostic biomarker for prostatic adenocarcinoma, has been recently proposed by Yoshida et al. (2020) as a unique marker of mesenchymal chondrosarcoma and EWSR1-NFATC2 sarcoma.
The aim of our study was to further explore utility of NKX3.1 as a diagnostic marker of mesenchymal chondrosarcoma.
MATERIAL & METHODS: We applied NKX3.1 immunohistochemistry to 21 cases of mesenchymal chondrosarcoma and 32 cases of other round blue cell tumors.
14 out of 21 cases (66.7%) of mesenchymal chondrosarcoma stained positive for NKX3.1 with nuclear expression in small round component. Cartilaginous component was predominantly negative. All other round blue cell tumors showed negative results.
Based on our study results we suggest that NKX3.1 is a useful immunohistochemical marker in differentiating mesenchymal chondrosarcoma from its histological mimics.
间叶性软骨肉瘤是软骨肉瘤的一种罕见亚型。该肿瘤具有特征性的双相模式，包含低分化小圆形细胞成分区域和散在的高分化透明软骨岛。间叶性软骨肉瘤的组织学诊断极具挑战性，尤其是在小活检标本中，此时肿瘤的软骨成分很少。在这种情况下，很难将间叶性软骨肉瘤与其他圆形蓝细胞肿瘤，如尤因肉瘤、横纹肌肉瘤、小细胞骨肉瘤和促纤维组织增生性圆形蓝细胞肿瘤区分开来。免疫组织化学方面，间叶性软骨肉瘤对NKX2.2、CD99、S100和SOX9呈阳性染色。这种免疫表型不具有特异性，与其他圆形蓝细胞肿瘤有重叠。直到最近，还没有可靠的免疫组织化学标志物来区分间叶性软骨肉瘤与其他圆形蓝细胞肿瘤。NKX3.1虽然被广泛用作前列腺腺癌的诊断生物标志物，但吉田等人（2020年）最近提出它是间叶性软骨肉瘤和EWSR1-NFATC2肉瘤的独特标志物。
我们研究的目的是进一步探讨NKX3.1作为间叶性软骨肉瘤诊断标志物的效用。
我们对21例间叶性软骨肉瘤和32例其他圆形蓝细胞肿瘤应用了NKX3.1免疫组织化学方法。
21例间叶性软骨肉瘤中有14例（66.7%）NKX3.1染色呈阳性，在小圆形成分中呈核表达。软骨成分主要为阴性。所有其他圆形蓝细胞肿瘤均显示阴性结果。
基于我们的研究结果，我们认为NKX3.1是区分间叶性软骨肉瘤与其组织学相似肿瘤的一种有用的免疫组织化学标志物。
