Department of Diagnostic Pathology, Faculty of Medicine, Oita University, Oita, Japan.
Department of Diagnostic Pathology, Faculty of Medicine, Oita University, Oita, Japan.
Oral Surg Oral Med Oral Pathol Oral Radiol. 2020 Apr;129(4):e230-e233. doi: 10.1016/j.oooo.2019.09.007. Epub 2019 Sep 16.
Desmoplastic fibroma of bone (DFB), a bone tumor, is considered to be an osseous counterpart of desmoid-type fibromatosis (DF). Herein, we report a case of DFB with CTNNB1 point mutation. The 5-year-old male patient had complained of trismus and pain in the jaw. Magnetic resonance imaging revealed a mass in the left mandible. Radical treatment involved surgical resection. Microscopically, the lesion consisted of a bundle-like proliferation of uniform spindle-shaped cells with abundant collagenous stroma, which resembled DF. Immunohistochemical analysis revealed intranuclear accumulation of β-catenin in the tumor cells. Based on clinical and histologic analysis, we diagnosed the patient as having DFB. We examined the CTNNB1 and APC sequence and found an A-to-G transition at codon 41 of CTNNB1; i.e., Thr was substituted by Ala. Our findings suggest that the dysregulation of Wnt/β-catenin signaling pathway is related to the tumorigenesis of some cases of DFB. This hypothesis indicates that there are some cases of DFB in which nuclear positive expression of β-catenin is useful for diagnosis.
骨促纤维性纤维瘤（DFB），一种骨肿瘤，被认为是纤维瘤病型（DF）的骨对应物。在此，我们报告一例 CTNNB1 点突变的 DFB。该 5 岁男性患者主诉牙关紧闭和下颌疼痛。磁共振成像显示左下颌骨有一肿块。根治性治疗包括手术切除。显微镜下，病变由束状增生的均匀梭形细胞和丰富的胶原基质组成，类似于 DF。免疫组化分析显示肿瘤细胞内β-连环蛋白核内聚集。根据临床和组织学分析，我们诊断该患者为 DFB。我们检查了 CTNNB1 和 APC 序列，发现 CTNNB1 密码子 41 处的 A 到 G 转换；即 Thr 被 Ala 取代。我们的发现表明，Wnt/β-连环蛋白信号通路的失调与某些 DFB 的肿瘤发生有关。这一假设表明，有些 DFB 病例中β-连环蛋白的核阳性表达有助于诊断。
