Renal cysts are classified according to Bosniak’s classification of simple and complicated cysts:
| |
Cyst type |
Description |
Procedure (approach) |
| Simple cysts |
Type I |
Benign (benign) renal cyst:
- Fluid-filled, invisible or filmy cyst wall,
- In ultrasound sound amplification behind the cyst, no septa (septum/cross-walls), no calcification (calcium deposition) in the cyst wall, no solid portions,
- No contrast enhancement in computed tomography (CT) and magnetic resonance imaging (MRI).
|
No follow-up required |
| Type II |
Benign, minimally complicated cyst
- Few, thin septa, fine calcification in the septa or cyst wall.
- Hyperdense (dense) lesions:
- Thickened, but still homogeneous content,
- Sharply demarcated wall, with no contrast uptake and no tissue content (cysts with thickened content corresponding; containing blood degradation products or proteins).
|
| Complicated cysts |
Type IIF |
- Minimal thickening of cyst wall or septa,
- Thick or granular calcifications,
- No portions with contrast uptake yet.
|
Follow up is required to rule out any change in cyst characteristics or growth. |
| Type III |
- Thickening of the cyst wall or septa,
- Irregular or granular, possibly with contrast uptake on CT.Malignancy (malignancy) cannot be excluded in this appearance. However, it may also be infected or bled cysts.
|
Surgical intervention required |
| Type IV |
- Clearly cystic malignancy (renal cancer) with irregular, solid, contrast-enhancing tissue as a malignancy criterion.
|
