恶性肿瘤的自然消退极为罕见，但肾细胞癌（RCC）最常与这种现象相关。我们报告了一例有肾细胞癌个人病史的患者，该患者接受了肾切除术且未接受其他肿瘤治疗。肾切除术后一年，发现肺转移并随访三年。它的大小随着时间的推移而增加，直到进行针活检并证实其转移性质。对肺结节进行楔形切除，未发现肿瘤细胞，表明活检后其自然消退。人们提出了不同的理论来解释这种现象，在大多数情况下，该机制似乎涉及免疫系统的激活。该病例支持了减轻肿瘤负荷和仪器引起的肿瘤微环境扰乱的重要性，以改善免疫系统的激活及其在肿瘤消退中的重要作用。

Spontaneous regression of malignant neoplasms is extremely rare, but renal cell carcinomas (RCC) are most often associated with this phenomenon. We report a case of a patient with personal history of RCC, who underwent nephrectomy and no other oncological treatment. One year after nephrectomy, a lung metastasis was detected and kept under follow-up for 3 years. Its size increased over time until a needle biopsy was performed, and its metastatic nature confirmed. Wedge resection of the lung nodule was performed, and no neoplastic cells were found, suggesting its spontaneous regression after biopsy. Different theories have been proposed to explain this phenomenon and, in most cases, the mechanism seems to involve the activation of the immune system. This case supports the importance of reducing tumor burden and the impact of the disturbance of the tumor microenvironment caused by instrumentation, in improving immune system activation and its essential role in neoplasm regression.