骨坏死是骨细胞因血液供应不足而死亡；针对各种潜在恶性肿瘤的放射治疗是不常见的原因之一。微血管损伤或潜在组织纤维化导致缺血环境和细胞死亡，是一种拟议的机制。影响放射诱发 AVN 风险的因素包括放射类型（无论是外照射放射治疗还是近距离放射治疗）、患者年龄（包括身体部位）以及伴随的额外类固醇或化疗治疗。在本病例报告中，我们带来了一例40岁男性患者，患有右股近端平滑肌肉瘤，接受了手术切除和辅助放疗，大约一年后进行了盆腔MR以评估手术床和右侧股骨头AVN的肿瘤进展经检测，该患者无症状。导致 AVN 的确切截止辐射剂量尚不清楚，并且因研究而异，因此即使是无症状患者，也需要对辐射场内的关节进行谨慎研究，以进行早期诊断并防止与延迟诊断相关的发病率。© 2024 作者。由爱思唯尔公司代表华盛顿大学出版。

Osteonecrosis is the death of bone cells due to insufficient blood supply; radiotherapy for various underlying malignancies is one of the uncommon causes. Microvascular damage or underlying tissue fibrosis, which leads to an ischemic environment and cell death, is a proposed mechanism. Factors influencing risk of radiation induced AVN include type of radiation whether external beam radiotherapy or brachytherapy, age of the patient, included body part and concomitant additional steroid or chemotherapy treatment. In this case report we brought a case of 40-year-old male patient with right proximal thigh leiomyosarcoma who underwent surgical resection and adjuvant radiotherapy, about a year later when Pelvic MR was done for evaluation of surgical bed and tumor progress right femoral head AVN was detected, the patient was asymptomatic. The exact cut-off radiation dose that causes AVN is unknown and varies across studies, necessitating a cautious study of joints included in the radiation field even in asymptomatic patients for early diagnosis and to prevent morbidity associated with delayed diagnosis.© 2024 The Authors. Published by Elsevier Inc. on behalf of University of Washington.