Introduction: Chondroblastoma (CB) is a rare, benign cartilage-producing tumor, typically affecting the epiphysis of long bones in skeletally immature individuals. There have been only limited case reports describing the cytomorphologic features of this tumor, and thus the cytopathologic diagnostic criteria are controversial. Herein, we report the cytologic findings of 10 CB cases, discuss the diagnostic criteria and critical differential diagnosis, along with a comprehensive review of the literature. Methods: We performed a retrospective search of our cytopathology and surgical pathology databases for cases diagnosed as CB that had corresponding cytology specimens from four large medical institutions. All available cytopathology specimens were retrieved and reviewed. Clinicopathologic and radiologic data were recorded. Results: Ten cases were retrieved from eight patients aged 15 to 42 years (mean, 24 years), five of whom were males. Eight cases represented primary tumors while two cases were recurrences. Three cases occurred in the femur, two cases occurred in the humerus, while one case occurred in each of the glenoid, talus, and proximal phalanx of the 3rd toe. The cytologic diagnosis of CB was achieved in seven cases. The neoplastic mononuclear cells were present in all cases and their cytologic features were similar. These cells displayed round to oval eccentric nuclei, evenly distributed chromatin, and inconspicuous nucleoli; few of which had nuclear indentations. Multinucleated giant cells were present in nine cases (90%). Fragments of chondromyxoid matrix were present in four cases on cytologic preparations (40%). Cell blocks were available in eight cases. Mononuclear and multinucleated giant cells were present in all adequate cell blocks and their cytologic features were identical to those seen in the smears. The chondroid matrix was present in only three of the adequate cell blocks (43%). Conclusion: We concluded that with the appropriate clinical and radiologic setting, the diagnosis of CB can be achieved on cytology if characteristic chondroblasts are present. The presence of chondromyxoid matrix is a helpful clue but is not necessary for the diagnosis. As in surgical pathology, cytologic evaluation of bone tumors should be interpreted in conjunction with clinical and radiologic findings.


中文翻译：

---

软骨母细胞瘤：10例细胞形态学分析并文献复习

简介：软骨母细胞瘤 (CB) 是一种罕见的良性软骨肿瘤，通常影响骨骼未成熟个体的长骨骨骺。只有有限的病例报告描述了这种肿瘤的细胞形态学特征，因此细胞病理学诊断标准存在争议。在此，我们报告10例CB病例的细胞学检查结果，讨论诊断标准和关键鉴别诊断，并对文献进行全面回顾。方法：我们对我们的细胞病理学和外科病理学数据库进行了回顾性检索，查找来自四家大型医疗机构的具有相应细胞学标本的诊断为 CB 的病例。检索并审查所有可用的细胞病理学标本。记录临床病理学和放射学数据。结果：共回收10例患者8例，年龄15～42岁（平均24岁），其中男性5例。8例为原发肿瘤，2例为复发肿瘤。股骨 3 例，肱骨 2 例，关节盂、距骨、第 3 趾近节指骨各 1 例。7例获得CB细胞学诊断。所有病例均存在肿瘤性单核细胞，且其细胞学特征相似。这些细胞呈圆形至椭圆形偏心核，染色质分布均匀，核仁不明显；其中很少有核凹痕。九例（90%）存在多核巨细胞。四例细胞学制剂中存在软骨粘液样基质碎片（40%）。细胞块在八个案例中可用。单核和多核巨细胞存在于所有足够的细胞块中，并且它们的细胞学特征与涂片中所见的相同。软骨样基质仅存在于三个足够的细胞块中（43%）。结论：我们的结论是，通过适当的临床和放射学设置，如果存在特征性成软骨细胞，则可以通过细胞学诊断 CB。软骨粘液样基质的存在是一个有用的线索，但对于诊断不是必需的。与外科病理学一样，骨肿瘤的细胞学评估应结合临床和放射学结果进行解释。