2022年，全球新发肺癌病例约106.06万例。肺癌少见转移部位有胰腺（5%~10%）、胃肠道、肾脏、心脏、皮肤（多见于小细胞肺癌），而肺癌转移至精囊腺者十分罕见，易被漏诊、误诊。本文报道1例表现为排尿困难、前列腺肿大的患者，经超声及腹部盆腔增强CT检查显示，右侧精囊腺存在肿物；胸部CT增强检查则显示右肺上叶占位。患者经右肺占位穿刺活检病理学检查，结果证实为腺癌，结合免疫组化标志物甲状腺转录因子1（thyroid transcription factor-1，TIF-1）、Napsin阳性，考虑为原发性肺腺癌。精囊腺肿物穿刺活检病理学检查结果证实为低分化腺癌，免疫组化标志物癌抗原125（cancer antigen 125，CA125）、细胞角蛋白7抗体（cytokeratin 7，CK7）、前列腺特异性抗原（prostate-specific antigen，PSA）、重组细胞角蛋白（recombinant cytokeratin 20，CK20）阴性，TIF-1、Napsin阳性，考虑为肺癌转移至精囊腺。综合相关检查结果最终诊断患者为肺腺癌Ⅳ期，予埃克替尼片125 mg靶向治疗，并在CT引导下在肺部病灶及精囊腺病灶中植入¹²⁵碘粒子进行放射治疗，2个月后复查病灶均未见进展。本病例报道充实了肺癌转移部位谱的诊治案例，临床需进一步总结肺癌精囊腺转移患者的临床特点、预后情况。

Lung cancer is one of the most common malignancies worldwide. In 2022, there were approximately 1 060 600 newly-diagnosed cases globally. Uncommon metastatic sites of lung cancer include the pancreas (5%-10%), gastrointestinal tract, kidneys, heart, skin (more common in small cell lung cancer). Among these, lung cancer metastasis to the seminal vesicle is extremely rare and prone to being missed or misdiagnosed. This paper reports a case of a patient presen-ting with dysuria and prostate enlargement: Ultrasonography and enhanced CT of the abdomen and pelvis showed a mass in the right seminal vesicle, and enhanced CT of the chest showed a space-occupying lesion in the upper lobe of the right lung. Pathological examination of a puncture biopsy of the right lung lesion confirmed adenocarcinoma. Based on positive immunohistochemical markers (TIF-1 and Napsin), it was diagnosed as primary lung adenocarcinoma. Pathological examination of a puncture biopsy of the seminal vesicle mass confirmed poorly differentiated adenocarcinoma,and immunohistochemical markers were negative for CA125, CK7, PSA, and CK20, but positive for TIF-1 and Napsin, suggesting lung cancer metastasis to the seminal vesicle. Based on comprehensive examinations, the patient was finally diagnosed with stage Ⅳ lung adenocarcinoma. Molecular targeted therapy with 125 mg of icotinib tablets was administered, and ¹²⁵I seeds were implanted in both the lung and seminal vesicle lesions under CT guidance for radiotherapy. Follow-up of two months showed no progression of the lesions. This case report enriches the spectrum of metastatic sites of lung cancer and highlights the need to further summarize the clinical characteristics and prognosis of patients with seminal vesicle metastasis from lung cancer.