Background & objective: Adrenal cortical adenoma (ACA) is a common disease, and can be diagnosed easily with CT examination. However, some atypical adenomas are likely to be misdiagnosed. This study was to evaluate the common and uncommon CT features of ACA to improve the diagnostic accuracy.
Methods: Common and uncommon CT features of 109 cases of histologically proved ACA were analyzed.
Results: Of the 109 cases of ACA, 104 showed unilateral single adenoma, 1 showed unilateral 2 adenomas, and 4 showed bilateral adenomas. The maximal diameter of the tumor was <5 cm in 95 patients. The maximal diameter of non-functional adenomas was larger than that of Cushing's adenomas, and the latter was larger than that of Conn's adenomas. The maximal diameter of the tumor was > 5 cm in 14 patients. The probability of degeneration was higher in large adenomas than in small adenomas. The CT images of 85 cases before and after contrast administration were assessed: 74 presented homogenous, 11 presented heterogenous; 76 presented slight to moderate enhancement, and 9 presented remarkable enhancement. Two patients had recurrence after operation: 1 showed infiltration in the adjacent kidney and the psoas major on pathologic examination, 1 showed infiltration in the liver and thoracic vertebra on CT images.
Conclusions: The common CT features of ACA include unilateral and single lesion, with the maximal diameter of <5 cm, homogenous density before contrast administration, and slight to moderate enhancement after administration. The uncommon CT features of ACA include bilateral or unilateral and multiple lesions, with the maximal diameter of >5 cm, heterogenous density before contrast administration, and remarkable enhancement after administration, recurrence, even canceration, metastasis after operation.