Stolte Sebastian J, Geiger Hanna, Forrer Flavio, Rodriguez Regulo, Müller Joachim
Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
Department of Pathology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
Front Nucl Med. 2023 May 17;3:1150143. doi: 10.3389/fnume.2023.1150143. eCollection 2023.
Intraosseous hibernoma (IOH) mimicking osseous metastasis is a rare and little-known pitfall in nuclear medicine and radiology. Referring to a clinical case, we show imaging features in FDG-PET and CT as well as pathological characteristics and discuss MRI and differential diagnoses. A 73-year-old woman was assigned for an FDG-PET/CT examination after the incidental finding of a suspicious pulmonary nodule. The FDG-PET/CT examination detected a small slightly FDG-avid pulmonary nodule suspicious for malignancy and a small slightly sclerotic lesion with mild FDG-uptake in the upper pubic bone. Histopathology revealed an intraosseous hibernoma, a rare benign soft-tissue tumor arising from brown fat. In the sparse literature available, intraosseous hibernomas may or may not be positive on bone scans. As in our case, most are slightly sclerotic on CT but lytic lesions have also been described. On MRI, they are T1 hypointense to subcutaneous fat and hyperintense to skeletal muscle; they are usually T2 hyperintense and may show peripheral contrast enhancement. According to the literature, IOHs are mostly incidental findings with solitary lesions in the spine, pelvis, ribs, or, very rarely, in the extremities with low to moderately increased glucose metabolism. IOHs present as painless tumors in general; a few painful cases could be successfully treated with radiofrequency ablation or surgery. Differential diagnoses include metastases, lymphoma, fibrous dysplasia, and non-ossifying fibroma among others. Intraosseous hibernoma is a rare benign tumor that can mimic metastases in FDG-PET, CT, bone scan, and MRI. IOHs might be indistinguishable from metastases or malignant lesions, which makes a biopsy or follow-up mandatory in clinically relevant cases. Given the benign nature of IOHs, radiofrequency ablation or surgery is only an option in symptomatic cases.
骨内冬眠瘤（IOH）酷似骨转移瘤，是核医学和放射学中一种罕见且鲜为人知的陷阱。通过一个临床病例，我们展示了FDG-PET和CT的影像特征以及病理特征，并讨论了MRI表现和鉴别诊断。一名73岁女性在偶然发现可疑肺结节后接受了FDG-PET/CT检查。FDG-PET/CT检查发现一个FDG摄取略高的小肺结节，怀疑为恶性，以及耻骨上缘一个FDG摄取轻度增加的小的轻度硬化性病变。组织病理学显示为骨内冬眠瘤，这是一种罕见的起源于棕色脂肪的良性软组织肿瘤。在现有的少量文献中，骨内冬眠瘤在骨扫描上可能呈阳性，也可能不呈阳性。如我们的病例所示，大多数在CT上呈轻度硬化，但也有溶骨性病变的描述。在MRI上，它们相对于皮下脂肪呈T1低信号，相对于骨骼肌呈高信号；通常呈T2高信号，可能显示周边强化。根据文献，骨内冬眠瘤大多为偶然发现，孤立性病变位于脊柱、骨盆、肋骨，或极罕见地位于四肢，葡萄糖代谢轻度至中度增加。骨内冬眠瘤一般表现为无痛性肿瘤；少数疼痛病例可通过射频消融或手术成功治疗。鉴别诊断包括转移瘤、淋巴瘤、骨纤维异常增殖症和非骨化性纤维瘤等。骨内冬眠瘤是一种罕见的良性肿瘤，在FDG-PET、CT、骨扫描和MRI上可酷似转移瘤。骨内冬眠瘤可能与转移瘤或恶性病变难以区分，这使得在临床相关病例中进行活检或随访成为必要。鉴于骨内冬眠瘤的良性性质，射频消融或手术仅适用于有症状的病例。
