van Langevelde K, Cleven A H G, Navas Cañete A, van der Heijden L, van de Sande M A J, Gelderblom H, Bovée J V M G
Department of Radiology, Leiden University Medical Center, Leiden, Netherlands.
Department of Pathology, Leiden University Medical Center, Leiden, Netherlands.
Sarcoma. 2022 Jun 17;2022:3425221. doi: 10.1155/2022/3425221. eCollection 2022.
Malignancy in giant cell tumor of bone (mGCTB) is categorized as primary (concomitantly with conventional GCTB) or secondary (after radiotherapy or other treatment). Denosumab therapy has been suggested to play a role in the etiology of secondary mGCTB. In this case series from a tertiary referral sarcoma center, we aimed to find distinctive features for malignant transformation in GCTB on different imaging modalities. Furthermore, we assessed the duration of denosumab treatment and lag time to the development of malignancy.
From a histopathology database search, 6 patients were pathologically confirmed as having initial conventional GCTB and subsequently with secondary mGCTB.
At the time of mGCTB diagnosis, 2 cases were treated with denosumab only, 2 with denosumab and surgery, 1 with multiple curettages and radiotherapy, and 1 with surgery only. In the 4 denosumab treated patients, the mean lag time to malignant transformation was 7 months (range 2-11 months). Imaging findings suspicious of malignant transformation related to denosumab therapy are the absence of fibro-osseous matrix formation and absent neocortex formation on CT, and stable or even increased size of the soft tissue component.
In 4 patients treated with denosumab, secondary mGCTB occurred within the first year after initiation of treatment. Radiotherapy-associated mGCTB has a longer lag time than denosumab-associated mGCTB. Close clinical and imaging follow-up during the first months of denosumab therapy is key, as mGCTB tends to have rapid aggressive behavior, similar to other high-grade sarcomas. Nonresponders should be (re) evaluated for their primary diagnosis of conventional GCTB.
骨巨细胞瘤（mGCTB）的恶性肿瘤分为原发性（与传统骨巨细胞瘤同时存在）或继发性（放疗或其他治疗后）。地诺单抗治疗被认为在继发性mGCTB的病因中起作用。在这个来自三级转诊肉瘤中心的病例系列中，我们旨在寻找不同影像学模式下骨巨细胞瘤恶性转化的独特特征。此外，我们评估了地诺单抗治疗的持续时间和发生恶性肿瘤的延迟时间。
通过组织病理学数据库搜索，6例患者经病理证实最初患有传统骨巨细胞瘤，随后发展为继发性mGCTB。
在mGCTB诊断时，2例仅接受地诺单抗治疗，2例接受地诺单抗和手术治疗，1例接受多次刮除术和放疗，1例仅接受手术治疗。在4例接受地诺单抗治疗的患者中，恶性转化的平均延迟时间为7个月（范围2 - 11个月）。与地诺单抗治疗相关的可疑恶性转化影像学表现为CT上无纤维骨性基质形成和新皮质形成缺失，以及软组织成分大小稳定甚至增加。
在4例接受地诺单抗治疗的患者中，继发性mGCTB在治疗开始后的第一年内发生。放疗相关的mGCTB比地诺单抗相关的mGCTB有更长的延迟时间。地诺单抗治疗的前几个月密切的临床和影像学随访是关键，因为mGCTB往往具有快速侵袭性行为，类似于其他高级别肉瘤。对无反应者应重新评估其传统骨巨细胞瘤的初步诊断。
