不同密度胸腺囊肿CT表现差异及其病理基础

目的：探讨不同密度胸腺囊肿CT表现差异及其病理基础。方法：回顾分析手术病理证实的45例实性密度胸腺囊肿和23例液性密度胸腺囊肿CT表现及其病理改变。结果：胸腺囊肿密度与囊肿大小有相关性（P＜0.01）。实性密度囊肿形态多较规则，液性密度囊肿以不规则、沿大血管间隙塑形多见，组间分布差异有统计学意义（P＜0.01）。泪滴状及三角状在2组均可见，组间分布差异无统计学意义（P＞0.05）。实性密度囊肿多不膨隆于胸腺轮廓，与液性密度相比差异有统计学意义（P＜0.01）。实性密度胸腺囊肿病理表现为有分泌功能的假复层纤毛柱状上皮或纤毛柱状上皮覆盖，囊壁上皮细胞排列较密实，囊液多浑浊；液性密度胸腺囊肿被覆表面为无分泌功能扁平或柱状上皮为主，排列稀疏甚至缺失，基层薄弱，囊液往往较清亮。囊肿密度与被覆上皮类型有相关性（P＜0.05）。结论：胸腺实性密度囊肿与液性密度囊肿影像学表现有差异，病理基础对理解不同表现胸腺囊肿有帮助。

CT findings of thymic cysts with different densities and their pathological basis

Objective: To explore the CT manifestations of thymic cysts with different densities and their pathological basis. Methods: The CT findings and pathological changes of 45 cases of thymic cysts with solid density and 23 thymic cysts with liquid density confirmed by operation and pathology were retrospectively analyzed. Results: There was a correlation between the density of thymic cysts and the distribution of size (P<0.01). The shape of the solid density cysts was regular, while the liquid density cyst was irregularly shaped along the large vessel gap. There was a significant difference between different groups (P<0.01). However, tear droplets and triangles were found in both groups without significant difference in the distribution between the two groups (P>0.05). Compared with the liquid density cysts, the solid density cysts were mostly not herniated outside the thymus profile, and the difference was statistically significant (P<0.01). The pathologic features of solid density thymic cysts included pseudostratified ciliated columnar epithelium or ciliated columnar epithelium with secretory function, dense arrangement of the epithelial cells of the cyst wall, and turbid cystic fluid. The surface of the liquid density thymic cysts was composed mainly of non-secretory flattened or columnar epithelium, sparse or even absent, the weak base layer and usually clear cystic fluid. There was significant difference between cyst density and epithelial type (P<0.05). Conclusion: The imaging findings of the solid density thymic cysts were different from liquid density thymic cysts. Their pathologic basis was helpful to understand the different manifestations of thymic cysts.