Department of Orthopaedic Surgery, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
Section of Orthopaedic Surgery, Department of Medicine, Fukuoka Dental College, Fukuoka, Japan;
In Vivo. 2022 Sep-Oct;36(5):2525-2529. doi: 10.21873/invivo.12989.
Localized tenosynovial giant cell tumor (LTGCT) is one of the most common benign soft-tissue tumors of the foot. Although pressure erosion in the adjacent bone may be seen, intraosseous invasion of LTGCT is extremely rare. Recent molecular studies have identified the presence of pathognomonic translocation involving the colony stimulating factor 1 (CSF1) gene at 1p13.
We present an unusual case of LTGCT mimicking a malignant tumor on imaging. The patient was a 16-year-old woman with no history of trauma who presented with a 2-year history of a slow-growing, painless mass in the left fourth toe. Physical examination revealed a 2-cm, elastic hard, immobile, nontender mass. Plain radiograph showed a lytic lesion with a partially sclerotic rim in the proximal phalanx of the fourth toe. Computed tomography demonstrated an expansile lesion with plantar cortical destruction. Magnetic resonance imaging revealed a nodular mass with intermediate signal intensity on T1-weighted sequences and heterogeneous high signal intensity on T2-weighted sequences. The mass had intense contrast enhancement. Complete excision of the mass was performed, and the bone defect was repaired with calcium phosphate cement. Cytogenetic analysis revealed a t(1;2)(p13;q37) translocation as the sole anomaly. Fluorescence in situ hybridization demonstrated the presence of CSF1 rearrangements.
Although extremely rare, LTGCT should be considered in the differential diagnosis of an intraosseous lesion near small joints, especially when seen in the toe.
局限性腱鞘巨细胞瘤（LTGCT）是足部最常见的良性软组织肿瘤之一。虽然可能会看到相邻骨的压迫性侵蚀，但 LTGCT 的骨内侵犯极为罕见。最近的分子研究已经确定了存在特征性易位，涉及集落刺激因子 1（CSF1）基因在 1p13 上。
我们报告了一个不常见的 LTGCT 病例，在影像学上模拟恶性肿瘤。患者为 16 岁女性，无外伤史，左第四趾有 2 年缓慢生长、无痛性肿块史。体格检查发现一个 2cm 大小、弹性硬、不可移动、无触痛的肿块。平片显示第四趾近节指骨溶骨性病变，部分硬化缘。计算机断层扫描显示膨胀性病变，伴有足底皮质破坏。磁共振成像显示 T1 加权序列中等信号强度、T2 加权序列不均匀高信号强度的结节状肿块。肿块有强烈的对比增强。完整切除肿块，并用磷酸钙水泥修复骨缺损。细胞遗传学分析显示 t(1;2)(p13;q37)易位为唯一异常。荧光原位杂交显示 CSF1 重排的存在。
尽管极为罕见，但在小关节附近的骨内病变的鉴别诊断中应考虑 LTGCT，尤其是在脚趾中见到时。
