Department of Nuclear Medicine, King Hussein Cancer Center, Amman, Jordan.
Department of Pathology and Lab medicine, King Hussein Cancer Center, Amman, Jordan.
J Egypt Natl Canc Inst. 2021 Oct 18;33(1):30. doi: 10.1186/s43046-021-00089-x.
Brown tumors are benign osteoclastic bone lesions encountered in patients with hyperparathyroidism. These tumors may demonstrate aggressive, destructive features in the skeleton and imitate metastatic bone lesions, particularly in patients with known primary neoplasm. In this case report of recurrent papillary thyroid cancer and ectopic parathyroid adenoma, we shed light on the importance of combining different nuclear medicine imaging modalities to differentiate brown tumors from metastatic bone lesions.
We present a 39-year-old woman with a known history of papillary thyroid carcinoma classic type stage pT1N1b post-total thyroidectomy and radioactive iodine (I-131) therapy (RAI) presented with upper limb weakness and pain. An expansile lytic lesion involving the 6th cervical vertebra was seen in cervical spine MRI, which was suspicious for metastatic deposit. Therapeutic and diagnostic I-131 whole-body scans were negative for any I-13-avid lesions. Laboratory results revealed high calcium, parathyroid hormone, and alkaline phosphatase. A Technetium-99m-sestamibi (Tc-99m MIBI) scan was done with the standard protocol of spot views to the neck and upper chest area to localize any suspicious parathyroid adenoma. The scan demonstrated right supraclavicular and mediastinal Tc-99m MIBI-avid lesions suspicious for being ectopic parathyroid adenomas. Whole-body fluorine-18-2-fluoro-2-deoxy-D-glucose (F-FDG), positron emission tomography/computed tomography (PET/CT) (F-FDG PET/CT) was performed for further evaluation. It demonstrated multiple focal lytic skeletal lesions of abnormal increased FDG uptake as well as right supraclavicular FDG-avid lymph nodes. However, the superior mediastinal lesion was non-FDG-avid, suggesting the existence of two different entities: ectopic parathyroid adenoma with multiple brown tumors and metastatic right supraclavicular lymph nodes. The patient underwent right neck dissection and superior mediastinal mass excision. An intra-operative fresh serum parathyroid sample was sent, which dropped down to 100ng/ml from 863.7ng/ml. Later, histopathological results revealed that the right supraclavicular lymph nodes were metastatic papillary thyroid carcinoma. At the same time, the superior mediastinal mass proved to be parathyroid adenoma by histopathology, confirming the F-FDG PET/CT findings.
In the case of papillary thyroid carcinoma, metastatic lymph nodes with hyperparathyroidism, and evidence of lytic bone lesions, careful interpretation of the different metabolic and functional imaging modalities are needed to exclude the concurrent parathyroid adenoma and facilitate the differentiation of brown tumors from bone metastases, leading to appropriate surgical and medical treatment plans.
棕色瘤是甲状旁腺功能亢进症患者中遇到的良性破骨细胞性骨病变。这些肿瘤在骨骼中可能表现出侵袭性、破坏性特征，并模仿转移性骨病变，特别是在已知原发性肿瘤的患者中。在复发性甲状腺乳头状癌和异位甲状旁腺腺瘤的病例报告中，我们强调了结合不同核医学成像方式来区分棕色瘤和转移性骨病变的重要性。
我们介绍了一位 39 岁女性，患有经典型甲状腺乳头状癌，pT1N1b 期，甲状腺全切术后接受放射性碘（I-131）治疗（RAI）。患者出现上肢无力和疼痛，颈椎 MRI 显示第 6 颈椎溶骨性病变，疑似转移性病灶。治疗和诊断性 I-131 全身扫描未见任何 I-131 摄取病灶。实验室结果显示血钙、甲状旁腺激素和碱性磷酸酶升高。进行了锝-99m-甲氧基异丁基异腈（Tc-99m MIBI）扫描，采用颈部和上胸部区域的标准点视图方案定位任何可疑的甲状旁腺腺瘤。扫描显示右侧锁骨上和纵隔 Tc-99m MIBI 摄取病灶，疑似异位甲状旁腺腺瘤。进行全身氟-18-2-氟-2-脱氧-D-葡萄糖（F-FDG）、正电子发射断层扫描/计算机断层扫描（PET/CT）（F-FDG PET/CT）进一步评估。显示多个局灶性溶骨性骨病变，FDG 摄取异常增加，以及右侧锁骨上 FDG 摄取淋巴结。然而，纵隔上病变无 FDG 摄取，提示存在两种不同的实体：异位甲状旁腺腺瘤伴多发棕色瘤和右侧锁骨上转移性淋巴结。患者接受了右侧颈部清扫术和纵隔肿块切除术。术中新鲜血清甲状旁腺样本送检，从 863.7ng/ml 降至 100ng/ml。随后，组织病理学结果显示右侧锁骨上淋巴结为转移性甲状腺乳头状癌。同时，纵隔肿块通过组织病理学证实为甲状旁腺腺瘤，证实了 F-FDG PET/CT 的发现。
在甲状腺乳头状癌、伴有甲状旁腺功能亢进症的转移性淋巴结和溶骨性骨病变的情况下，需要仔细解读不同的代谢和功能成像方式，以排除同时存在的甲状旁腺腺瘤并有助于区分棕色瘤和骨转移，从而制定适当的手术和治疗计划。
