Koo Hyun-Lyoung, Jang Jaejung, Hong Suck-Joon, Shong Youngkee, Gong Gyungyub
Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, 388-1, Pungnap-dong, Songpa-gu, Seoul, 138-736, South Korea.
Acta Cytol. 2004 Jan-Feb;48(1):64-8. doi: 10.1159/000326285.
Renal cell carcinoma is an unpredictable tumor that can recur many years after the original diagnosis and metastasize to uncommon sites, including the thyroid gland. Differential diagnosis from primary thyroid tumor is often difficult both clinically and pathologically. We report a case of metastatic renal cell carcinoma in follicular adenoma of the thyroid gland.
A 48-year-old woman presented with a 3-cm-diameter, palpable mass in the left lobe of the thyroid gland. The patient's history included removal of a left renal mass, which was conventional renal cell carcinoma. Fine needle aspiration cytology smears contained a few small clusters of polygonal cells with abundant, clear cytoplasm and irregular, hyperchromatic nuclei as well as bland-looking thyroid follicle cells and stromal cells. A papillary or follicular growth pattern was not detected. A cell block made from the aspirated sample was composed mainly of clear cells. By immunohistochemical stains, the clear cells were completely negative for TTF-1, thyroglobulin, calcitonin and inhibin while equivocally staining for cytokeratin, CD10 and galectin-3. The histologic diagnosis was renal cell carcinoma metastatic to follicular adenoma of the thyroid gland.
Renal cell carcinoma metastatic to the thyroid may masquerade as a primary thyroid neoplasm. A history of prior nephrectomy, the presence of unremarkable thyroid follicle cells, the absence of a papillary or follicular growth pattern and immunohistochemical study can help differentiating metastatic renal cell carcinoma from a primary thyroid lesion with clear cell change.
肾细胞癌是一种难以预测的肿瘤，可在最初诊断多年后复发，并转移至包括甲状腺在内的不常见部位。在临床和病理上，与原发性甲状腺肿瘤进行鉴别诊断往往很困难。我们报告一例甲状腺滤泡性腺瘤中转移性肾细胞癌的病例。
一名48岁女性，甲状腺左叶可触及一个直径3厘米的肿块。患者既往有左肾肿块切除史，病理为传统型肾细胞癌。细针穿刺细胞学涂片包含一些小簇多边形细胞，其细胞质丰富、清亮，细胞核不规则、深染，以及外观平淡的甲状腺滤泡细胞和基质细胞。未检测到乳头状或滤泡状生长模式。由穿刺样本制成的细胞块主要由透明细胞组成。免疫组化染色显示，透明细胞对甲状腺转录因子-1（TTF-1）、甲状腺球蛋白、降钙素和抑制素完全阴性，而对细胞角蛋白、CD10和半乳糖凝集素-3染色不明确。组织学诊断为转移性肾细胞癌至甲状腺滤泡性腺瘤。
转移至甲状腺的肾细胞癌可能会伪装成原发性甲状腺肿瘤。既往肾切除术史、存在不显著的甲状腺滤泡细胞、不存在乳头状或滤泡状生长模式以及免疫组化研究有助于将转移性肾细胞癌与具有透明细胞改变的原发性甲状腺病变区分开来。
