Bockhorn Maximilian, Sheu Sien-Yi, Frilling Andreja, Molmenti Ernesto, Schmid Kurt W, Broelsch Christoph E
Department of General Surgery and Transplantation Surgery, University Hospital Essen, Germany.
Thyroid. 2005 Dec;15(12):1363-7. doi: 10.1089/thy.2005.15.1363.
The wide variety of rare histologic variants of medullary thyroid carcinoma (MTC) may make the differential diagnosis difficult. Pathologic examination of the resected specimen will not always be able to confirm the diagnosis, leaving the surgeon with an uncertainty as to what type of resection is best for the patient. The following report describes the case of a 58-year-old man with the rare diagnosis of paraganglioma-like MTC.
The patient presented with markedly elevated calcitonin (CT) and carcinoembryonic antigen (CEA) levels. A 1-cm tumor was detected in the right lobe of the thyroid. Based on the clinical diagnosis of MTC, we performed a total thyroidectomy with lymphadenectomy of the central and right lateral compartments. Paraffin sections of the resected specimen were stained with hematoxylin and eosin (H&E) and immunohistochemically characterized using antibodies to CT, CEA, chromogranin A, thyroglobulin, synaptophysin, sustentacular cells (SCs), low- and high-molecular cytokeratins (CK 5/6, 7, 18, 20), epidermal growth factor-receptor (EGFR), thyroid transcription factor-1 (TTF-1), bcl-2, Melan A, C-kit, neuron-specific enolase (NSE), and galectin-3. The patient's blood and tumor tissue were examined for mutations in the RET-protooncogene.
H&E staining of both frozen and permanent sections was unable to differentiate benign from malignant tissue. Typical morphologic characteristics for MTC were completely absent. Only the additional finding of positivity for synaptophysin and numerous SC cells visible in-between neoplastic cells made the diagnosis of paraganglioma-like MTC possible. Sequencing of the RET proto-oncogene revealed no mutations.
There are subgroups of MTC that present clinically similar to classic MTC, but in which missing typical morphologic characteristics make histopathology diagnosis difficult. In these cases, diagnosis, operative decisions, and follow-up strategies should be based on preoperative biochemical markers, imaging findings, and clinical parameters in accordance to the guidelines for classic MTC.
甲状腺髓样癌（MTC）存在多种罕见的组织学变异型，这可能会使鉴别诊断变得困难。对切除标本进行病理检查并不总能确诊，这使得外科医生难以确定何种类型的切除术对患者最为合适。以下报告描述了一例罕见的类副神经节瘤样MTC的58岁男性病例。
该患者降钙素（CT）和癌胚抗原（CEA）水平显著升高。在甲状腺右叶检测到一个1厘米的肿瘤。基于MTC的临床诊断，我们进行了全甲状腺切除术，并对中央区和右侧颈侧区进行了淋巴结清扫。切除标本的石蜡切片用苏木精和伊红（H&E）染色，并使用针对CT、CEA、嗜铬粒蛋白A、甲状腺球蛋白、突触素、支持细胞（SCs）、低分子量和高分子量细胞角蛋白（CK 5/6、7、18、20）、表皮生长因子受体（EGFR）、甲状腺转录因子-1（TTF-1）、bcl-2、Melan A、C-kit、神经元特异性烯醇化酶（NSE）和半乳糖凝集素-3的抗体进行免疫组织化学特征分析。对患者的血液和肿瘤组织进行RET原癌基因突变检测。
冰冻切片和永久切片的H&E染色均无法区分良性与恶性组织。完全没有MTC的典型形态学特征。仅突触素阳性以及在肿瘤细胞之间可见大量支持细胞这一额外发现使得类副神经节瘤样MTC的诊断成为可能。RET原癌基因测序未发现突变。
MTC的某些亚组在临床上与经典MTC相似，但缺乏典型的形态学特征，这使得组织病理学诊断困难。在这些情况下，诊断、手术决策和随访策略应根据经典MTC的指南，基于术前生化标志物、影像学检查结果和临床参数来制定。
