Objective: To investigate the pathological features and the clinicopathological significance of TERT detection in those tumors that were difficult to diagnosis. Methods: A total of 93 cases of fibroepithelial tumors without definite diagnosis were collected from the Affiliated Hospital of Qigndao University between 2013 and 2021. The clinical details such as patients' age and tumor size were collected. All slides were re-reviewed and the pathologic parameters, including stromal cellularity, stromal cell atypia, stromal cell mitoses, and stromal overgrowth were re-interpreted. Sanger sequencing was used to detect TERT promoter status, and immunohistochemistry was performed to detect TERT protein expression. The relationship between TERT promoter mutation as well as protein expression levels and the clinicopathological parameters were also analyzed. Results: The patients' ages ranged from 30 to 71 years (mean of 46 years); the tumor size ranged from 1.2 to 8.0 cm (mean 3.8 cm). These tumors showed the following morphologic features: leafy structures in the background of fibroadenoma, or moderately to severely abundant stromal cells. The interpretations of tumor border status were ambiguous in some cases. The incidence of TERT promoter mutation was high in patients of age≥50 years, tumor size≥4 cm, and stromal overgrowth at ×4 or ×10 objective, and these clinicopathologic features were in favor of diagnosis of phyllodes tumors. TERT protein expression levels was not associated with the above clinicopathologic parameters and its promoter mutation status. Conclusions: The diagnostic difficulty for the breast fibroepithelial tumors is due to the difficulty in recognition of the leafy structures or in those cases with abundant stromal cells. A comprehensive evaluation combined with morphologic characteristics and molecular parameters such as TERT promoter may be helpful for the correct diagnosis and better evaluating recurrence risk.
目的： 探讨诊断困难的乳腺纤维上皮性肿瘤的病理学特点，分析TERT检测的临床病理学意义。 方法： 收集青岛大学附属医院病理科2013—2021年93例诊断结果不确定的乳腺纤维上皮性肿瘤患者的年龄、肿瘤大小等信息；重新复习病理切片，对间质细胞密度、间质细胞不典型性、核分裂象及间质生长程度等形态学指标进行判读；采用Sanger测序检测TERT启动子突变，采用免疫组织化学染色研究TERT蛋白在间质细胞中的表达情况，分析TERT启动子突变及TERT蛋白表达水平同临床病理参数的相关性。 结果： 本组病例年龄30~71岁，平均年龄46岁；肿瘤最大径1.2~8.0 cm（平均3.8 cm）；病理学特点：纤维腺瘤区域中存在分叶状结构，或者间质细胞中至重度丰富；一部分病例肿瘤边界的判读存在困难；TERT启动子突变，在年龄≥50岁、肿瘤≥4 cm、出现4倍及10倍物镜下无上皮区间质生长的病例中发生率更高，这些特点更符合叶状肿瘤；TERT蛋白表达水平与临床病理特点以及TERT启动子的突变无相关性。 结论： 对分叶状结构的判断争议以及间质细胞丰富肿瘤的分类争议，是乳腺纤维上皮性肿瘤诊断困难的原因；结合形态学特点及TERT启动子等分子指标进行综合评估，有助于明确诊断以及更好地评估复发风险。.