Ghost cell odontogenic carcinoma (GCOC) is an extremely rare intraosseous malignant odontogenic tumor with prominent ghost cell keratinization and dentinoid formation. Here, we present the first case of GCOC arising in dentinogenic ghost cell tumor (DGCT), peripheral. The patient was a man in his 60s with an exophytic mass in the anterior part of lower gingiva. The resected tumor measured 4.5 cm in maximum diameter. Histologically, the nonencapsulated tumor proliferated in the gingiva without bone invasion. It was predominantly composed of ameloblastoma-like nests and islands of basaloid cells with ghost cells and dentinoid in the mature connective tissue, suggesting DGCT, peripheral. As minor components, sheets of atypical basaloid cells and ameloblastic carcinoma-like nests with pleomorphism and high proliferative activity (Ki-67 labeling index up to 40%) consistent with malignancy were identified. CTNNB1 mutation and β-catenin nuclear translocation were observed in both benign and malignant components. Final diagnosis was GCOC arising in DGCT, peripheral. GCOC shows similar histological features to DGCT. In this unique case without invasion, the cytological atypia and high proliferative activity supports the diagnosis of malignant transformation from DGCT.

中文翻译：

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牙本质鬼细胞瘤中出现的牙源性鬼细胞癌，外周：一例报告

鬼细胞牙源性癌（GCOC）是一种极其罕见的骨内恶性牙源性肿瘤，具有显着的鬼细胞角化和牙本质形成。在此，我们介绍第一例由牙本质源性鬼细胞瘤 (DGCT) 引起的外周 GCOC 病例。患者为60多岁男性，下牙龈前部有一个外生肿块。切除的肿瘤最大直径为 4.5 厘米。组织学上，非包膜肿瘤在牙龈中增殖，没有骨侵犯。它主要由成釉细胞瘤样巢和基底样细胞岛组成，成熟结缔组织中有鬼细胞和牙本质，提示 DGCT，外周。作为次要成分，鉴定出具有多形性和高增殖活性（Ki-67 标记指数高达 40%）的非典型基底细胞片和成釉细胞癌样巢，与恶性肿瘤一致。在良性和恶性成分中均观察到CTNNB1突变和 β-catenin 核转位。最终诊断为 DGCT 中出现的 GCOC，外周。GCOC 表现出与 DGCT 相似的组织学特征。在这种没有侵袭的独特病例中，细胞学异型性和高增殖活性支持 DGCT 恶性转化的诊断。