Deé Edith, Loghin Andrada, Nechifor-Boilă Adela, Neagoe R, Paşcanu Ionela, Borda Angela
Department of Histology, University of Medicine and Pharmacy of Tirgu Mures, Romania;
Rom J Morphol Embryol. 2013;54(4):1121-4.
The aim of the study is to present the unusual changes that a lymph node metastasis of papillary thyroid carcinoma (PTC) underwent after radioiodine therapy, leading to the confusion with a parathyroid adenoma (PA).
Eight years after a total thyroidectomy and radioiodine ablation with 73.35 mCurie 131I for PTC, a 67-year-old female presented with an enlarged, painless, nodular mass in the left lateral neck region. Clinical examination revealed a firm nodule located on the site of the left inferior parathyroid gland. Elevated serum parathyroid hormone level (120 pg/mL) and parathyroid scintigraphy led to a suspicion of PA. A minimally invasive surgical procedure was performed to remove the mass, which was sent to the Department of Pathology, Emergency County Hospital, Tirgu Mures, Romania, as left PA. It was fixed and processed for microscopic evaluation.
On macroscopic examination, the surgical specimen was oval; it had 13 mm at the largest diameter and weighted 2 g. On microscopy, the lesion appeared as a fibro-hyaline, intensely acidophilic, acellular mass, with calcifications. It was limited by a delicate capsule in which one typical psammoma body was present. At the periphery, on one single level, a small mass of cells of indefinite origin was noticed. Immunohistochemistry (IHC) was done to ascertain the origin of these cells: they were negative for Pan-Cytokeratin AE1/AE2, Parathormone and Thyroglobulin antibodies, but positive for Leukocyte Common Antigen (LCA) antibody, proving that they were lymphocytes, most likely residual from a lymph node.
These IHC data, together with the microscopic feature, the presence of the psammoma body and the patient's history, excluded a PA and led to a diagnosis of fibro-hyaline involution of a PTC metastasis in a lymph node, consecutive to radioiodine therapy. Without careful microscopic examination and accurate clinical information, this lesion could represent a real diagnostic challenge.
本研究旨在呈现甲状腺乳头状癌（PTC）淋巴结转移灶在放射性碘治疗后所经历的异常变化，从而导致与甲状旁腺腺瘤（PA）相混淆。
一名67岁女性在因PTC行全甲状腺切除及73.35毫居里131I放射性碘消融治疗8年后，左侧颈部外侧区域出现一个肿大、无痛的结节状肿块。临床检查发现一个质地坚硬的结节位于左下甲状旁腺所在部位。血清甲状旁腺激素水平升高（120 pg/mL）及甲状旁腺闪烁显像引发了对PA的怀疑。遂进行了微创手术切除该肿块，并将其作为左侧PA送至罗马尼亚特尔古穆列什县急救医院病理科。对其进行固定并处理以进行显微镜评估。
大体检查时，手术标本呈椭圆形；最大直径为13毫米，重2克。显微镜下，病变表现为纤维透明样、嗜酸性强、无细胞的肿块，并伴有钙化。其被一层薄包膜所包绕，包膜内可见一个典型的砂粒体。在周边，仅在一个层面上，发现一小团来源不明的细胞。进行了免疫组织化学（IHC）检查以确定这些细胞的来源：它们对泛细胞角蛋白AE1/AE2、甲状旁腺激素和甲状腺球蛋白抗体呈阴性，但对白细胞共同抗原（LCA）抗体呈阳性，证明它们是淋巴细胞，很可能是淋巴结残留的。
这些IHC数据，连同显微镜特征、砂粒体的存在及患者病史，排除了PA，并得出诊断为放射性碘治疗后PTC淋巴结转移灶的纤维透明样退变。若没有仔细的显微镜检查和准确的临床信息，该病变可能会构成真正的诊断挑战。
