Takahashi Yusuke, Motoi Toru, Harada Masahiko, Fukuda Yumiko, Hishima Tsunekazu, Horio Hirotoshi
From the Department of Thoracic Surgery (YT, MH, HH); and Department of Pathology (TM, YF, TH), Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Bunkyo-ku, Tokyo, Japan.
Medicine (Baltimore). 2015 Jan;94(1):e366. doi: 10.1097/MD.0000000000000366.
Benign notochordal cell tumors (BNCTs) are tumors originating in the axial skeleton, where chordomas occur. Although very rare, some cases of extraosseous chordoma, such as in the soft tissue and lungs, have been reported. We report a case of a primary tumor showing the notochordal characteristics of BNCTs within the axial skeleton.An asymptomatic 57-year-old woman presented with an abnormal shadow on her chest radiograph; chest computed tomography revealed a well-defined round nodule. The resected sample tissue contained a jelly-like small nodule. Histologically, it was identified as a BNCT, based on minimal nuclear atypia, extremely low mitotic activity within the tumor cells lying in a sheet-like arrangement, and focal immunopositivity for brachyury.This is the third case report of BNCT originating in the lungs; BNCTs are considered asymptomatic tumors that are identified by using highly developed chest imaging technology; however, our findings also suggest that these notochordal tumors may potentially originate from extraosseous sites that lack ideal precursor cells. Our case suggests that notochordal tumors can arise from organs that are unrelated to known notochordal development.
良性脊索细胞瘤（BNCTs）是起源于轴骨（脊索瘤发生的部位）的肿瘤。尽管非常罕见，但也有一些骨外脊索瘤的病例报道，如发生于软组织和肺部的。我们报告一例原发性肿瘤，其在轴骨内表现出BNCTs的脊索瘤特征。
一名57岁无症状女性胸部X线片显示异常阴影；胸部计算机断层扫描显示一个边界清晰的圆形结节。切除的样本组织包含一个果冻样小结节。组织学上，基于核异型性极小、呈片状排列的肿瘤细胞内有丝分裂活性极低以及对brachyury的局灶免疫阳性，该肿瘤被鉴定为BNCT。
这是第三例起源于肺部的BNCT病例报告；BNCTs被认为是通过高度发达的胸部成像技术识别出的无症状肿瘤；然而，我们的研究结果还表明，这些脊索瘤可能潜在地起源于缺乏理想前体细胞的骨外部位。我们的病例表明，脊索瘤可起源于与已知脊索发育无关的器官。
