孤立纤维性肿瘤（SFTs）是罕见的间叶性肿瘤，通常起源于胸膜，但也可发生在体内各个部位。虽然关于非胸膜SFTs的报道越来越多，但骨骼SFTs的报道非常罕见，尚未报道过伴有骨盆复发的恶性SFT。本文报道了一例15岁男性患者，其右臀部出现间歇性麻木，并伴有下肢放射性疼痛6个月。放射学检查显示骶骼和髂骨区域有一个扩张的、异质性增强的肿块，右内髂动脉的分支供血给肿瘤。组织学检查提示恶性SFT，其增殖活性较高。骶骼肿块经手术切除。手术后，患者在9个月时出现局部肿瘤复发，并接受辅助亲鸟苷治疗。最近的磁共振成像增强显示肿瘤萎缩，这可能为治疗骨盆恶性SFT复发提供了某些证据。完全手术切除是这种罕见疾病的推荐治疗方法，辅助治疗的作用由于其罕见性而有争议。我们的案例强调了处理复发性恶性SFTs的挑战，并强调了彻底的诊断工作的重要性。需要进一步研究确定辅助治疗在这些肿瘤的管理中的作用。版权所有 © 2023 作者。由 Wolters Kluwer Health, Inc. 发布。

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms that typically arise from the pleura but can also occur in various locations throughout the body. Although there are increasingly more reports of extra-pleural SFTs, reports of SFTs in bone are very rare, and a malignant SFT accompanying recurrence of pelvis has not yet been reported.We herein present the case of a 15-year-old male who experienced intermittent numbness in his right buttock, accompanied by radiating pain in his lower limbs for 6 months. Radiological examinations revealed an expansive, heterogeneous enhanced mass in the sacral and iliac regions, with a branch of the right internal iliac artery feeding the tumor.The histological examination suggest a diagnosis of a malignant SFT with high proliferation activity.The sacral mass was surgically excised.Following the surgery, the patient experienced a local recurrence of the tumor at 9 months and was administered adjuvant imatinib treatment. Recent magnetic resonance imaging contrast-enhanced displayed shrinkage of the tumor, which may provide certain evidence for chemotherapy for the treatment of recurrence of malignant SFTs in the pelvic region.Complete surgical excision is the recommended treatment for this rare disease entity, and the role of adjuvant therapies is controversial due to their rarity. Our case underscores the challenges in managing recurrent malignant SFTs and highlights the importance of a thorough diagnostic workup. Further research is needed to establish the role of adjuvant therapies in the management of these tumors.Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.