患者,男,17岁,体检时偶然发现右下肺块状影两个月,无症状。既往体健。检查无阳性发现。X线胸片示:右下肺圆形块影直径约5cm,界限清楚密度均匀,无分叶。手术见右下肺前内基底段5cm直径圆形肿块,质硬,纵膈淋巴结不肿大,作右下肺叶切除术。病理检查示:瘤细胞呈棱形,胞浆丰富,边界清楚(见插页图2),束状交织成栅状排列,致密,外周有纤维组织包膜(见插页图1)诊断:肺良性平滑肌瘤。术后患者痊愈出院。讨论虽然平滑肌瘤在消化道中和子宫肌内是最 The patient, male, was 17 years old. He had accidentally discovered a blocky shadow of the right lower lung during physical examination for two months and was asymptomatic. Past health. Check for no positive findings. X-ray showed: the diameter of the right lower lung circular block is about 5cm, the boundary is clear and uniform density, no splitting. The surgery saw a 5 cm diameter round mass in the basal segment of the right lower lung, hardened, and no mediastinal lymph nodes were enlarged for right lower lobe resection. Pathological examination showed that the tumor cells were prismatic, with abundant cytoplasm, well-defined borders (see inset in Figure 2), bundles interlaced in a grid-like arrangement, and dense, peripheral fibrous tissue envelope (see inset in Figure 1) Diagnosis: benign smooth lung Fibroids. The patient was cured and discharged. Although leiomyoma is the most common in the digestive tract and in the uterine muscle,