原发性甲状腺淋巴瘤^(18)F-FDG PET/CT显像特征

Characteristics of primary thyroid lymphoma in ^(18)F-FDG PET/CT

目的:探讨原发性甲状腺淋巴瘤(PTL)在^(18)F-FDG PET/CT显像中的代谢及影像特征。方法:回顾性分析经病理证实的PTL(PTL组)及甲状腺癌(甲状腺癌组)各15例,并对患者临床特征及^(18)F-FDG PET/CT图像特征进行对比分析。结果:15例PTL9例为弥漫大B细胞淋巴瘤(DLBCL),3例为黏膜相关淋巴样组织淋巴瘤(MALT),2例为滤泡性淋巴瘤(FL),1例为伯基特淋巴瘤(BL)。15例甲状腺癌中11例乳头状癌,3例滤泡癌,1例髓样癌。PTL组SUVmax为9.8±7.7,甲状腺癌SUVmax为5.2±3.7,差异有统计学意义(t=2.097,P<0.05);侵袭性组(DLBCL、BL)SUVmax为10.6±8.4,与甲状腺癌组对比差异有统计学意义(t=1.848,P<0.05),惰性组(FL、MALT)SUVmax为8.5±7.0,与甲状腺癌组比较差异无统计学意义(t=1.445,P>0.05)。PTL组病灶最大径(4.0±2.6)cm,甲状腺癌病灶最大径(2.2±1.6)cm,差异有统计学意义(t=2.250,P<0.05)。PTL组9例为弥漫型,而甲状腺癌组8例为单发结节型,差异有统计学意义(χ^(2)=12.873,P<0.05)。PTL组在峡部增厚率(8/15)、伴有钙化比例(3/15)、病灶边界不清楚比例(12/15)及累及气管、食管比例方面与甲状腺癌组比较差异均有统计学意义(P<0.05)。结论:PTL在^(18)F-FDG PET/CT显像中有一定的特征,多表现为甲状腺弥漫性肿大,密度均匀减低,少见囊变、钙化,^(18)F-FDG摄取明显均匀性增高,有别于常见的甲状腺癌^(18)F-FDG PET/CT表现。

Objective:To analyze the metabolic and imaging characteristics of primary thyroid lymphoma(PTL)in ^(18)F-FDG PET/CT imaging.Methods:Clinical data and ^(18)F-FDG PET/CT images of 15 patients with PTL(PTL group)and 15 patients with thyroid cancer(thyroid cancer group)confirmed by pathology were retrospectively analyzed.Results:Among the 15 cases of PTL,9 cases were diffuse large B-cell lymphoma,3 cases were mucosa-associated extranodal tissue lymphoma,2 cases were follicular cell lymphoma,and 1 case was Burkitt's lymphoma.Among the 15 thyroid cancers,11 were papillary carcinoma,3 were follicular carcinomas,and 1 was medullary carcinoma.SUVmax of the PTL group(9.8±7.7)was higher than that of the thyroid cancer group(5.2±3.7),with a statistically significant difference(t=2.097,P<0.05).The SUVmax of the invasive lymphoma group(DLBCL,BL)was 10.6±8.4,which wad also significantly different from the thyroid cancer group(t=1.848,P<0.05),whereas the SUVmax of the indolent lymphoma group(FL,MALT)was 8.5±7.0,showing no statistically significant difference compared to the thyroid cancer group(t=1.445,P>0.05).The maximum diameter of the lesion showed significant differences between the PTL and thyroid cancer groups(t=2.250,P<0.05).In the PTL group,9 cases were of the diffuse type,while in the thyroid cancer group,8 cases were of the single nodular type,and the difference was statistically significant(χ^(2)=12.873,P<0.05).There were statistically significant differences between the PTL group and thyroid cancer group in terms of isthmus thickening rate(53.3%,8/15),the proportion of calcification(20.0%,3/15),the proportion of unclear lesion boundary(80.0%,11/15)and the proportion of trachea and esophagus involvement(P<0.05).Conclusion:PTL exhibits specific characteristics in ^(18)F-FDG PET/CT imaging,primarily characterized by diffuse enlargement of the thyroid gland,uniform loss of density,rare cystic degeneration and calcification,and significant uniform increase in ^(18)F-FDG uptake.These findings distinguish PTL from the common ^(18)F-FDG PET/CT manifestations of thyroid cancer.