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. 2020 Jan 3;11(1):5.
doi: 10.1186/s13244-019-0826-3.

CT and MR imaging of cystic renal lesions

Francesco Agnello  1 , Domenico Albano  2   3 , Giuseppe Micci  2 , Giuseppe Di Buono  4 , Antonino Agrusa  4 , Giuseppe Salvaggio  2 , Salvatore Pardo  2 , Gianvincenzo Sparacia  2 , Tommaso Vincenzo Bartolotta  2   5 , Massimo Midiri  2 , Roberto Lagalla  2 , Massimo Galia  2
Affiliations
Free PMC article

CT and MR imaging of cystic renal lesions

Francesco Agnello et al. Insights Imaging. .
Free PMC article

Abstract

Cystic renal lesions are a common incidental finding on routinely imaging examinations. Although a benign simple cyst is usually easy to recognize, the same is not true for complex and multifocal cystic renal lesions, whose differential diagnosis includes both neoplastic and non-neoplastic conditions. In this review, we will show a series of cases in order to provide tips to identify benign cysts and differentiate them from malignant ones.

Keywords: Bosniak; CT; Cystic renal cell carcinoma; Cystic renal lesion; MR.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Cystic renal lesion in a 76-year-old-man. a Gray-scale ultrasound shows a cystic lesion (arrow) with a thin wall and thin septa (arrowhead), which contains fine calcifications. b Corresponding CEUS image shows enhancement of cyst wall and septa
Fig. 2
Fig. 2
Imaging features of cystic renal lesions according to Bosniak classification. a Bosniak category I cyst: thin wall. b Bosniak category II cyst: thin wall; few, thin septa. c Bosniak category II-F cyst: minimally thickened wall; several, minimally thickened septa. d Bosniak category III cyst: irregularly thickened wall; several, irregularly thickened septa. e Bosniak category IV cyst: enhancing nodularity; irregularly thickened wall; several, irregularly thickened septa
Fig. 3
Fig. 3
Bosniak category I renal cyst. Axial non-enhanced (a) and contrast-enhanced (b) CT images shows a cyst (arrow) with a thin and non-enhancing wall
Fig. 4
Fig. 4
Bosniak category I renal cyst. a Axial T2-weighted MR image shows a lesion (arrow) with strong hyperintensity and a thin wall. Corresponding axial non-enhanced (b) and contrast-enhanced (c) T1-weighted MR images show a hypointense lesion with a thin and non-enhancing wall
Fig. 5
Fig. 5
Bosniak category II renal cyst. a Axial non-enhanced CT image shows a lesion with a thin wall (arrow) and a thin septum (arrowhead), which contains fine calcifications. b Corresponding axial contrast-enhanced CT image shows enhancement of cyst wall and septum
Fig. 6
Fig. 6
Bosniak category IIF renal cyst. Axial non-enhanced CT image shows a lesion with irregular calcifications within the wall (arrow) and septa (arrowhead)
Fig. 7
Fig. 7
Bosniak category IIF renal cyst. Axial non-enhanced (a) and contrast-enhanced (b) CT images shows a large (> 3 cm) lesion (arrow) with spontaneous hyperattenuation and no enhancement
Fig. 8
Fig. 8
Bosniak category III renal cyst. Axial contrast-enhanced T1-weighted MR image shows a lesion with thick, enhancing wall and septa (arrow)
Fig. 9
Fig. 9
Bosniak category IV renal cyst. Axial contrast-enhanced T1-weighted MR image shows a lesion with a peripheral, enhancing, nodule (arrow)
Fig. 10
Fig. 10
Renal abscess. a Axial contrast-enhanced CT shows a cystic lesion (arrow) with a peripheral, thick, enhancing, wall. b Axial contrast-enhanced CT obtained 3 months after antibiotic therapy shows decrease in size of the lesion
Fig. 11
Fig. 11
Autosomal dominant polycystic kidney disease. Coronal T2-weighted image shows symmetric enlargement of the kidneys, which contain multiple cysts with variable size
Fig. 12
Fig. 12
Acquired cystic renal disease. Axial contrast-enhanced CT image shows atrophic kidneys, which contain multiple cysts of variable size
Fig. 13
Fig. 13
Localized cystic renal disease. Axial contrast-enhanced CT image shows a conglomeration of multiple simple cysts of variable size (arrow) in the right kidney
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