BACKGROUND Elastofibroma is a benign soft tissue tumor characterized by the presence of elastic fibers in a stroma of collagen and mature adipose tissue. It is reported to have a prevalence of 2.73%, as shown by a study through computed tomography (CT) images. However, multiple elastofibromas are uncommon. CASE PRESENTATION We report a case of concomitant bilateral elastofibroma in the infrascapular and gluteal regions. A 63-year-old male patient presented with a 6-month history of gradually increasing painless swellings in the upper back. On physical examination, firm, painless bilateral infrascapular masses were identified; these masses were more noticeable on forward arm flexion. Contrast-enhanced computed tomography showed well-defined bilateral infrascapular masses deep to the serratus anterior muscles as well as poorly defined bilateral gluteal masses with attenuation similar to that of the adjacent skeletal muscle. Magnetic resonance imaging revealed heterogenous masses with internal fatty streaks, consistent with elastofibroma. The histopathological diagnosis of elastofibroma was established based on the results of image-guided core-needle biopsy. The patient underwent surgical excision of both infrascapular elastofibromas with no post-operative complications. As the gluteal masses were incidental, surgical management was not warranted. CONCLUSION The presence of multiple elastofibromas is unusual. This report describes a rare case of multiple elastofibromas and its typical imaging features, and alerts us that elastofibromas are not exclusive to the periscapular region.

中文翻译：

---

肩cap下和臀区域伴有双侧弹力纤维瘤：一例罕见病例的报告。

背景技术弹性纤维瘤是一种良性软组织肿瘤，其特征在于胶原和成熟脂肪组织的基质中存在弹性纤维。通过计算机断层扫描（CT）图像进行的研究显示，据报道其患病率为2.73％。但是，多种弹性纤维瘤并不常见。病例介绍我们报告了肩cap下和臀肌区伴有双侧弹力纤维瘤的病例。一名63岁的男性患者出现了6个月的上背部无痛性肿胀逐渐增加的病史。体格检查发现牢固，无痛的双侧肩fra下肿块。这些质量在前臂弯曲时更明显。对比增强的计算机体层摄影术显示，在锯齿肌前肌深处有明确定义的双侧肩cap下肿块，以及与相邻骨骼肌相似的衰减程度较差的双侧臀肌块。磁共振成像显示具有内部脂肪条纹的异质性肿块，与弹性纤维瘤一致。弹性纤维瘤的组织病理学诊断是基于图像引导的穿刺活检的结果。该患者接受了两种肩cap下弹性纤维瘤的手术切除，无术后并发症。由于臀块是偶发性的，因此不需手术治疗。结论多个弹性纤维瘤的存在是不寻常的。本报告介绍了多种弹性纤维瘤的罕见情况及其典型的影像学特征，