一名61岁的男性患者在11年前接受了左胫骨肿瘤的切除手术，导致骨软化症。术后骨痛和疲劳症状短暂缓解，但随后复发。为了确定是否存在复发的可能性，进行了99mTc-HYNIC-TOC显像。图像显示右胫骨有一个骨溶解性病变，摄取增加。随后切除了病变，病理证实为褐色瘤。手术后4个月，由于骨软化症引起的骨痛和虚弱症状没有缓解。在这里，我们报道了一例少见的99mTc-HYNIC-TOC SPECT/CT高活性的褐色瘤病例，模拟了骨软化症的原因性肿瘤。

A 61-year-old man underwent a resection of tumor in the left tibia that caused osteomalacia 11 years ago. Postoperative bone pain and fatigue symptoms were briefly relieved but then recurred. To identify potential recurrent tumors, 99mTc-HYNIC-TOC scintigraphy was performed. Images revealed an osteolytic lesion in the right tibia with increased uptake. The lesion was subsequently resected, which pathologically proved a brown tumor. Symptoms of bone pain and weakness caused by osteomalacia did not relieve 4 months after the operation. Here, we present a rare case of brown tumor with high activity on 99mTc-HYNIC-TOC SPECT/CT, mimicking a culprit tumor of osteomalacia.Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.