Pyo Ju Yeon, Kim Jisup, Choi Sung Eun, Shin Eunah, Yang Seok Woo, Park Cheong Soo, Kim Seok Mo, Hong Soonwon
Department of Pathology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
Department of Pathology, CHA Gangnam Hospital, CHA University Medical School, Seoul, Korea.
Yonsei Med J. 2017 Jan;58(1):255-258. doi: 10.3349/ymj.2017.58.1.255.
We describe herein histologic, immunohistochemical, and molecular findings and clinical manifestations of a rare case of an extremely well differentiated papillary thyroid carcinoma (EWD-PTC). Similarly, it is also difficult to diagnose follicular variant papillary thyroid carcinoma (FVPTC), whose diagnosis is still met with controversy. A recently reported entity of well-differentiated tumor of uncertain malignant potential (WDT-UMP) is added to the diagnostic spectrum harboring EWD-PTC and FVPTC. We report this case, because EWD-PTC is different from FVPTC in its papillary architecture, and also from WDT-UMP in its recurrence and metastatic pattern. These morphologically deceptive entities harbored diagnostic difficulties in the past because the diagnosis depended solely on histology. However, they are now diagnosed with more certainty by virtue of immunohistochemical and molecular studies. We experienced a case of EWD-PTC, which had been diagnosed as adenomatous hyperplasia 20 years ago and manifested recurrence with lymph node (LN) metastasis 7 years later. After another 7 years of follow-up, a new thyroid lesion had developed, diagnosed as FVPTC, with LN metastasis of EWD-PTC. One year later, the patient developed metastatic FVPTC in the skull. Immunohistochemically, the EWD-PTC was focally positive for CK19, negative for galectin-3, and focally negative for CD56. Molecular studies revealed BRAF-positivity and K-RAS negativity. The FVPTC in the left thyroid showed both BRAF and K-RAS negativity. In conclusion, EWD-PTC and FVPTC share similar histologic features, but they are different tumors with different molecular biologic and clinical manifestations. A large cohort of EWD-PTC should be included in further study.
我们在此描述了一例极高度分化型乳头状甲状腺癌（EWD-PTC）罕见病例的组织学、免疫组织化学及分子学特征和临床表现。同样，滤泡状变异型乳头状甲状腺癌（FVPTC）的诊断也颇具难度，其诊断仍存在争议。最近报道的一种恶性潜能不确定的分化良好肿瘤（WDT-UMP）也被纳入了包含EWD-PTC和FVPTC的诊断范畴。我们报告此病例，是因为EWD-PTC在乳头状结构上与FVPTC不同，在复发和转移模式上也与WDT-UMP不同。这些在形态学上具有欺骗性的实体过去在诊断上存在困难，因为诊断仅依赖于组织学。然而，如今借助免疫组织化学和分子学研究能更确切地进行诊断。我们遇到一例EWD-PTC病例，该病例20年前被诊断为腺瘤样增生，7年后出现复发并伴有淋巴结（LN）转移。经过另外7年的随访，出现了一个新的甲状腺病变，被诊断为FVPTC，并伴有EWD-PTC的LN转移。1年后，患者颅骨出现FVPTC转移。免疫组织化学检测显示，EWD-PTC对CK19呈局灶性阳性，对galectin-3呈阴性，对CD56呈局灶性阴性。分子学研究显示BRAF呈阳性，K-RAS呈阴性。左甲状腺的FVPTC显示BRAF和K-RAS均为阴性。总之，EWD-PTC和FVPTC具有相似的组织学特征，但它们是不同的肿瘤，具有不同的分子生物学和临床表现。进一步的研究应纳入大量的EWD-PTC病例队列。
