Fetsch J F, Weiss S W
Department of Pathology, Mayo Clinic, Rochester, MN.
Hum Pathol. 1990 Jun;21(6):662-8. doi: 10.1016/s0046-8177(96)90014-3.
Four new cases of ectopic hamartomatous thymoma are presented. The tumor occurred either superficially or deep in the area of the sternoclavicular joint and consisted of solid islands of squamous epithelium which blended with spindled cells. Cysts lined by squamous epithelium, small glands, and fat also occurred in variable amounts. Both the spindled and epithelial regions of the tumor expressed keratin and muscle actin, but neither desmin nor S100 protein. The tumor probably originates from thymic anlage associated with the third pharyngeal pouch (thymus III), although origin from other structures such as thymus IV and the cervical sinus of His are discussed. Our experience indicates that the large size and extreme cellularity of the spindled portion of some tumors may result in the mistaken diagnosis of sarcoma.
本文报告了4例异位错构瘤性胸腺瘤。肿瘤发生于胸锁关节区域的浅表或深部，由鳞状上皮实性岛状结构与梭形细胞混合组成。鳞状上皮衬里的囊肿、小腺体和脂肪的含量也各不相同。肿瘤的梭形和上皮区域均表达角蛋白和肌动蛋白，但不表达结蛋白和S100蛋白。肿瘤可能起源于与第三咽囊相关的胸腺始基（胸腺III），不过也讨论了其起源于其他结构如胸腺IV和His颈窦的可能性。我们的经验表明，某些肿瘤梭形部分的大尺寸和极高细胞密度可能导致误诊为肉瘤。
