胸部髓外造血与髓脂肪瘤的CT与MRI鉴别诊断

The Differential CT/MRI Diagnosis of Thoracic Extramedullary Hematopoiesis and Myelolipoma

目的探讨胸部髓外造血与髓脂肪瘤的影像鉴别诊断特征。方法回顾分析经病理证实的5例髓外造血与2例髓脂肪瘤患者的临床资料及影像学表现,观察患者年龄、性别、基础疾病;分析病灶的部位、数目、形态、大小及密度、信号及强化特点;观察大体标本及镜下结构。结果胸部髓外造血患者平均年龄43.7岁,男女性别比1.5∶1;髓脂肪瘤患者平均年龄61岁,性别比无差异。髓外造血基础疾病包括地中海贫血1例,恶性贫血1例,溶血性贫血3例;髓脂肪瘤基础疾病含糖尿病1例,慢性阻塞性肺气肿1例。5例胸部髓外造血位于双侧脊柱旁,呈多发性,扁丘状或椭圆形,病灶直径1.2～3 cm,其中3例密度不均匀,信号混杂,增强后不均匀强化;2例为均匀等密度及中等信号,轻度均匀强化。2例髓脂肪瘤位于后纵隔脊柱旁,1例单发,1例双侧对称性,类圆形,直径约4～8 cm,呈等低混合密度及混合信号,以脂肪为主,轻度不均匀强化。髓外造血大体呈红色,镜下不含或含不同比例的脂肪,造血成分多;髓脂肪瘤黄红相间,以黄色为主,脂肪成分为主,含髓系细胞。结论胸部髓外造血与髓脂肪瘤患者在发病年龄、性别、基础疾病,病灶数目、形态及大小、密度、信号、颜色、病理均有差异,可以结合临床病史及影像学特点进行正确鉴别诊断。

Objective To identify the imaging features of thoracic extramedullary hematopoiesis（ TEMH） and Myelolipoma. Methods We retrospectively identified 7 patients（ 5 with TEMH; 2 with Myelolipoma）. Patients clinical data,including age,sexual distinction and any condition associated were recorded. The imaging characteristics such as location of lesion,number,shape,range and density,signal and enhancement pattern were analyzed and recorded; and pathology were recorded. Results The average age at diagnosis for those with myelolipomas（ 61 years） was significantly higher than that seen in TEMH（ 43. 7 years）. The TEMH sex ratio was 1. 5∶ 1,while there was no sex preference seen in myelolipomas. TEMHs were found in 1 thalassemia,1 pernicious anemia,3 hemolytic anemia. Myelolipomas were associated with 1diabetes and 1 chronic obstructive emphysema. Five TEMHs had multiple masses on both sides in the range of 1. 2- 3cm in diameter,3 TEMH patients show mixed density and mild enhancement because of fat deposition,while 2 patients were homogenous and mildly hyperintense to muscles on both T1 WI and T2 WI,and they show homogenous enhancement. 2 myelolipomas were located in mediastinum,with 1 single and 1 bilateral,which were circular,and the diameter range was 4-8cm. Contrast enhanced CT show mixed density and inhomogeneous enhancement,the same pattern as on MR imaging.TEMH was described as having red areas,with marrow elements outside the bone marrow,without or with different proportions of fat. Myelolipomas show yellow and red areas on cut section,having much adipose tissue mainly and bone marrow elements. Conclusion The clinical history including age,sexual distinction,primary diseases and imaging characteristics can help to differentiate thoracic extramedullary hematopoiesis and myelolipoma.