Objective To analyze the CT features of primary adrenal lymphoma (PAL)in order to improve the diagnosis of the disease.Methods Clinical and CT findings of 1 1 patients with pathologically confirmed PAL were retrospectively analyzed.Results 18 lesions (10 on the right side,and 8 on the left)were found in all 11 cases of PAL (bilateral lesions in 7 cases).The maximum diameter ranges of the lesions were from 3.8 cm to 12.0 cm (M ± SD:6.5±2.3 cm).The shapes of the lesions were shown as round (2/18),oval (9/18)or irregular (7/18).The plain CT showed all lesions with isodensity or lowGdensity,and the CT attenuation value ranged from 24.5 to 46.3 HU (mean 33.6±5.7 HU).The contrastGenhanced CT showed 16 lesions with slightGmoderate and gradual enhancement,1 lesion with nonenhancement and other 1 with severe enhancement.The CT value of the lesions ranged from 24.9 to 71.4 HU (M±SD:45.1 ± 12.1 HU)in arterial phase and 23.8 to 7 9.9 HU (M±SD:5 5.0±1 3.4 HU)in venous phase.The cystic degeneration in 8 lesions,infiltration of peripheral organs and vessels in 8 lesions,and peritumoral lymphadenectasis in 1 lesion were seen.In the 1 1 cases with 4－48 month followGup after chemotherapy,9 lesions decreased or disappeared,and other 2 decreased first but then increased.Conclusion PAL predominantly occurs in the bilateral adrenal glands and represents isoGlow density soft tissue mass on plain CT.Contrast enhanced CT shows the the solid parts of lesions mostly with mild to moderate gradual enhancement.In addition,the larger lesions are prone to have cystic degeneration and invade surrounding tissues and organs.

Objective To study the CT characteristics of adrenal metastasis (AM) and lipid-poor adrenal adenoma (Lp-AA).Methods We retrospectively analyzed clinical and CT dates of AM (n=25) and Lp-AA (n=61) which were pathologically or clinically confirmed.The size,location,number,contour,cystic degeneration,calcification,hemorrhage and the clinical data were analyzed,as well as,CT value of tumor were measured and calculated.Receiver operating characteristic (ROC) curves were employed to assess the significant continuous variables to tell AM from Lp-AA.Results 34 adrenal lesions were detected for 25 cases of AM (9 case showed bilateral with 18 lesions).There were 65 lesions for 61 cases of Lp-AA (3 cases showed bilateral and 1case showed two lesions in unilateral side).Sex and age had significant difference between the two groups (P＜0.05).On the categorical variables of CT examination,number,cystic degeneration and contour had significant difference between the two groups (P＜0.05),while tumor location,hemorrhage and calcification had no significant difference (P＞0.05).For the continuous variables,plain scan CT value,enhancement amplitude,relative percentage washout (RPW) and tumor size had significant difference between the two groups (P＜0.05).Area under ROC curve analysis showed that when the plain scan CT value＞30.4 HU,area under ROC curve,sensitivity and specificity were 0.878,91.2％,and 72.3％,respectively.When RPW was ＞-33.4％,the area under ROC curve,sensitivity and specificity were 0.643,79.4％,64.7％,respectively.When the maximum and minimum diameter of tumor were ＞2.9 cm and 2.2 cm respectively,the area under the curve,sensitivity,specificity were 0.762,73.5％,75.4％ and 0.706,64.7％,69.2％,respectively.When venous phase increase and the largest increase were ＜37.7 HU and 37.3 HU respectively,the area under the curve,sensitivity,specificity were 0.805,89.2％,64.7％ and 0.833,95.4％,64.7％ respectively.Conclusion Tumor size,number,contour,cystic degeneration,CT measured and calculated value,as well as the patients' clinical data are of great value in differentiating AM and Lp-AA.