We report an uncommon case of a 76-year-old woman who presented with lower back pain, an intermittent L5 radiculopathy and a right palpable paraspinal mass. Imaging studies revealed a 7-cm lumbar paraspinal pseudo-cystic soft tissue tumour developed in the paravertebral musculature, without a clear radiological diagnosis. Gross total surgical resection was performed, resulting in complete resolution of pain. Histopathological studies revealed an intramuscular (IM) myxoma.

With a low positive predictive value of radiological work-up and a poor yield of percutaneous biopsies, surgery remains the mainstay treatment for these rare soft tissue tumours of the lumbar spine. Intramuscular myxomas show excellent postoperative results.

我们报告了一个不常见的病例，一名 76 岁的女性出现腰痛、间歇性 L5 神经根病和右侧可触及的椎旁肿块。影像学研究显示，在椎旁肌肉组织中出现了一个 7 厘米长的腰椎椎旁假性囊性软组织肿瘤，但没有明确的放射学诊断。进行了总的手术切除，导致疼痛完全消退。组织病理学研究显示肌肉内 (IM) 粘液瘤。

由于放射检查的阳性预测值低且经皮活检的产量低，手术仍然是这些罕见的腰椎软组织肿瘤的主要治疗方法。肌内粘液瘤显示出良好的术后效果。