Kamekura S, Nakamura K, Oda H, Inokuchi K, Iijima T, Ishida T
Department of Orthopaedic Surgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
J Orthop Sci. 2001;6(2):183-6. doi: 10.1007/s007760100068.
Involuted intraosseous lipoma with extensive fat necrosis resulting in cyst formation (Milgram stage III) is distinguishable from lesions without necrosis (stage I) or lesions with focal fat necrosis (stage II), based on differences in signal intensity on magnetic resonance imaging (MRI). Fat tissue has a high signal intensity on both T1- and T2-weighted MR images, whereas the extensive fat necrosis that results in cyst formation shows high signal intensity on T2-weighted images and low intensity on T1-weighted images. We report a patient in whom an intraosseous lipoma with high signal intensity on both T1- and T2-weighted MRI was found to be extensively involuted on histopathologic examination. Intraosseous lipoma appears to undergo spontaneous involution. In some patients, therefore, surgical excision may not be necessary. A correct preoperative diagnosis should reduce the necessity for a biopsy or surgery. Although lesions classified as stage I or II are easily identified by MRI, those of stage III are difficult to diagnose preoperatively by this method.
伴有广泛脂肪坏死并形成囊肿的萎缩性骨内脂肪瘤（米尔格拉姆III期），根据磁共振成像（MRI）信号强度的差异，可与无坏死的病变（I期）或伴有局灶性脂肪坏死的病变（II期）相区分。脂肪组织在T1加权和T2加权磁共振图像上均具有高信号强度，而导致囊肿形成的广泛脂肪坏死在T2加权图像上显示高信号强度，在T1加权图像上显示低信号强度。我们报告1例患者，其骨内脂肪瘤在T1加权和T2加权MRI上均具有高信号强度，经组织病理学检查发现已广泛萎缩。骨内脂肪瘤似乎会自发萎缩。因此，在某些患者中，可能无需手术切除。正确的术前诊断应减少活检或手术的必要性。虽然I期或II期病变通过MRI很容易识别，但III期病变术前通过这种方法很难诊断。
