异位性错构瘤性胸腺瘤1例报道及文献复习

Ectopic hamartomatous thymoma:a case report and review of literature

目的探讨良性异位性错构瘤性胸腺瘤的临床病理特征及其鉴别诊断。方法石蜡包埋组织连续切片分别做HE染色和免疫组化染色,光镜观察,分析1例异位性错构瘤性胸腺瘤的临床病理学特征及免疫表型特征,并进行文献复习。结果肿块位于左颈部,生长缓慢。大体为结节状,包膜完整,切面部分囊性变。镜下显示肿瘤由梭形细胞、上皮样细胞、脂肪细胞和少量淋巴细胞组成。免疫组化染色显示:梭形细胞和上皮样细胞均弥漫性强阳性表达细胞角蛋白CK7、CK8、CK、CK5/6,不表达desmin、TTF-1、GFAP。此外,梭形细胞阳性表达p63、Calponin、SMA、CD10、CD34,不表达细胞膜抗原EMA。而与之相反的是上皮样细胞阳性表达EMA不表达SMA、CD10、CD34。结论异位性错构瘤性胸腺瘤是一种罕见的良性肿瘤,好发于中青年男性的颈部下方、锁骨上方及胸骨上方,需要与其它双向分化的肿瘤尤其是高级别肉瘤如滑膜肉瘤或腺样恶性外周神经鞘膜瘤鉴别,故该肿瘤的诊断及鉴别诊断尤为重要。

Purpose To investigate the clinicopathologic features,immunohistochemistry and differential diagnosis of rare ectopie hamartomatous thymoma （EHT）. Methods HE stains and immunohistochemical studies were performed on formalin-fixed paraffin-embedded issues in one case of EHT, and the clinical presentations, histopathological features and immunophenotype were studied in it. Simultaneously, the related literature was reviewed. Results A solitary mass in the left neck, which grew slowly in ten years. Grossly, the mass showed a solitary round shape and well-circumscribed, measuring 7 cm in maximum diameter. The cut surface of the tumor was light to dark yellow in color with soft to solid consistency and partial cystic degeneration. Histologically, the tumor was consisted of spindle cells, epithelial cells, mature adipose tissue and a small number of lymphocytes. Immunohistoehemically, both the spindle and epithe- lial cells were strongly positive for CK, CK5/6, CK7, CK8, but were negative for desmin ,TTF-1 and GFAP. The spindle cell component was also positive for p63 ,calponin, CD34, CD10 and SMA but not for EMA ,while the epithelial cell component was positive expression for EMA and negative for CD34,CDlO and SMA. Conclusions EHT is a rare benign tumor,which exclusively occurs in the supraelavicular, suprasternal or rarely in the presternal region, and more attention should be paid in differential diagnosis from malignant tumors with a biphasic pattern such as biphasic synovial sarcoma and glandular malignant peripheral nerve sheath tumor.