Department of Pathology and Cell Biology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Pathol Res Pract. 2013 Oct;209(10):674-8. doi: 10.1016/j.prp.2013.06.020. Epub 2013 Jul 15.
The patient presented here, a 74-year-old female, had a 3-year history of a gradually enlarging painless nodule in the right submental lateral region of the neck. A neck CT scan showed a well-demarcated cystic lesion, measuring 25mm in diameter, but without any definite evidence of neoplastic foci in the lymph nodes, thyroid gland, or lung. Clinicians first interpreted it as branchial cleft cyst, and a cystectomy was performed. Gross examination revealed a unilocular cystic lesion filled with yellowish clear fluids, containing a markedly thinned fibrous wall with smooth inner surface, partly coexisting with tiny solid and papillary-like components. On microscopic examination, the cystic tumor was lined by mono-layered ciliated columnar or metaplastic stratified squamous epithelium with underlying ectopic thyroid follicles or lymphocytic infiltrate, reminiscent of thyroglossal duct cyst (TDC), partly adjacent to the compressed lymph node tissue. Its solid parts were composed of a proliferation of atypical cuboidal to columnar epithelial cells with occasional nuclear grooves or intranuclear inclusions, arranged in a papillary growth pattern with supporting delicate fibrovascular cores. Immunohistochemically, these atypical cells were positive for thyroid transcription factor 1, thyroglobulin, and cytokeratin 19. Therefore, we finally made a diagnosis of papillary carcinoma (PC) arising in TDC in the lateral neck. Although metastatic thyroid PC of cervical lymph node was an important differential diagnosis owing to various overlapping clinicopathological features, coexistent benign lining epithelium or thyroid follicles, a histological hallmark of TDC, were present in the current case.
本例患者为 74 岁女性，右侧颏下外侧区有一逐渐增大的无痛性结节，病史 3 年。颈部 CT 扫描显示边界清楚的囊性病变，直径 25mm，但在颈部淋巴结、甲状腺或肺部均无明确的肿瘤灶证据。临床医生最初将其诊断为鳃裂囊肿，并进行了囊肿切除术。大体检查显示为单房囊性病变，充满淡黄色清亮液体，纤维壁明显变薄，表面光滑，部分与微小的实性和乳头状成分共存。镜下检查，囊性肿瘤由单层纤毛柱状或化生的复层鳞状上皮衬里，下方有异位甲状腺滤泡或淋巴细胞浸润，类似于甲状舌管囊肿（TDC），部分与受压的淋巴结组织相邻。其实性部分由增生的不典型立方柱状至柱状上皮细胞组成，偶见核沟或核内包涵体，呈乳头状生长模式，有纤细的纤维血管核心支持。免疫组化染色，这些不典型细胞甲状腺转录因子 1、甲状腺球蛋白和细胞角蛋白 19 阳性。因此，我们最终诊断为颈外侧 TDC 起源的甲状腺乳头状癌（PC）。虽然转移性甲状腺 PC 伴颈部淋巴结转移由于各种重叠的临床病理特征是重要的鉴别诊断，但在本例中存在 TDC 的组织学特征——共存的良性衬里上皮或甲状腺滤泡。
