毛细血管扩张性骨肉瘤很罕见，很少影响扁平骨，尤其是骨盆的骨头。在评估较大的腹内肿块时，将毛细血管扩张性骨肉瘤视为鉴别诊断的情况并不常见。我们介绍的病例是一名 33 岁的非洲女性，其左髂骨出现相当大的毛细血管扩张性骨肉瘤。她报告称，左胁部出现一个无痛、生长缓慢的肿块，持续了 3 年。检查时，发现有一个大的骨硬肿块从左髂骨延伸到脐部，几乎与腹内妊娠相似。所有实验室检查均在正常范围内，并采用非常规手术方法对肿瘤进行一期切除，无并发症。仅在第二次检查组织学标本时，切除后明确的组织病理学诊断为毛细血管扩张性骨肉瘤。骨盆毛细血管扩张性骨肉瘤很少见，髂骨是最常见的骨盆骨。这些肿瘤在就诊时可能相当大，并有腹腔内或盆腔扩展，误诊的可能性很高。幸运的是，周围软组织受累似乎是一种罕见且较晚的发现。© 2024。作者。

Telangiectatic osteosarcoma is rare and it rarely affects flat bones, especially the bones of the pelvis. It is uncommon for telangiectatic osteosarcoma to be considered as a differential diagnosis when assessing a large intrabdominal mass.We present our case of a 33-year-old African female who presented with a sizeable telangiectatic osteosarcoma of the left iliac bone. She reported a 3-year duration of a painless, slow-growing mass arising from the left flank. At examination, a large bony hard mass extending from the left ilium to the umbilicus was noted, almost mimicking an intra-abdominal pregnancy. All laboratory tests were within normal limits and an unconventional surgical approach was used for a one-stage excision of the tumor without complications. The definitive histopathological diagnosis postexcision was that of a telangiectatic osteosarcoma only on the second review of the histological specimen.Pelvic telangiectatic osteosarcoma is rare, and the ilium is the commonly affected pelvic bone. These tumors can be sizeable at presentation with intra-abdominal or pelvic extension with a high chance of misdiagnosis. Fortunately surrounding soft tissue involvement seems to be a rare and late finding when present.© 2024. The Author(s).