甲状腺透明细胞型乳头状癌临床病理观察

Clear-cell variant of papillary thyroid carcinoma:a clinicopathological study

目的探讨甲状腺透明细胞型乳头状癌的临床病理特征、免疫表型、诊断及鉴别诊断要点。方法对1例甲状腺肿瘤的临床病理资料进行光镜观察及免疫组化和AB-PAS染色,并复习相关文献。结果患者女性,60岁。肿瘤位于甲状腺峡部,大体呈结节状,似有完整包膜,切面五彩状,可见黏液及钙化。组织学见肿瘤由充满胶质或稀薄黏液的滤泡结构和实性片状区域构成,未见明确乳头结构,但可见泡状核、核沟及核内假包涵体,引人注目的是实性区域部分细胞胞质透明。免疫组化显示TTF-1、Tg、galectin-3和CK19(+),HBME-1、降钙素、CD10、RCC和vimentin(-)。特殊染色:AB-PAS(+)。结论甲状腺透明细胞型乳头状癌是甲状腺乳头状癌的罕见亚型,组织形态学易与转移性肾透明细胞癌混淆,免疫组化及PAS染色有助于二者的鉴别。

Abstract： Objective To study the clinicopathologic features, immunophenotype and differential diagnosis of clear-cell variant of papillary thyroid carcinoma （CPTC）. Methods The clinical and histopathologic features were analyzed in a case of CPTC. Immunohistochemical and AB-PAS stains were carried out on paraffin-embedded tissues, and relevant literatures were reviewed. Results A nodule from thyroid isthmic portion of a 60-year-old woman was analyzed. Grossly, the ovoid mass measured 4. 8 x 4 x 3.5 cm was encapsulated, firm, focally gelatinous, yellow and partially hemorrhagic. Microscopically, it was composed of solid areas and follicles filled with colloid or mucus. No papillay structure was seen. Ground-glass nuclei, nuclear groovings and pseudoinclusions were present. Some solid areas showed remarkably clear cells. Immunohistochemisty showed that all the tumor cells including clear ceils were positive for TFF-1, Tg, galectin-3 and CK19, and negative for HBME-1, calcitonin, CD10, RCC and vimentin. Periodic acid Schiff （PAS）-positive granules were seen in the cytoplasm of the tumor cells and Alcian blue （AB） -positive mucus was seen in the follicles. The colloid in the follicles was also PAS-positive. Conclusion CPTC is a rare variant of papillary thyroid carcinoma. It is difficult to make differential diagnosis from renal cell carcinoma metastatic to thyroid microscopically, and immunohistochemical and PAS staining may be of great help.