We present different cases of simple cysts that presented distinct complications such as Wunderlich syndrome (secondary to a spontaneous rupture of cyst in a kidney without prior injury and another in a kidney with acquired cystic kidney disease), retraction and partial emptying of a cyst after radiofrequency ablation of an adjacent tumor and infected cysts.
Wunderlich syndrome (WS) is a rare condition in which spontaneous nontraumatic renal hemorrhage occurs in the subcapsular and perirenal spaces.
The main imaging finding is hemorrhage in the perirenal spaces, often with a primary injury seen with the kidney such as acquired cystic kidney disease, as we are going to see in the first case.
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1. A 76-year-old man in hemodialysis due to acquired cystic kidney disease as we can appreciate at coronal reconstruction. 4 months later, this patient consulted for low back pain and hemodynamic instability. The urgent CT showed a retroperitoneal hematoma on the left side that it seemed to have a renal origin. Arteriography was performed and the left renal artery was embolized with a sclerosing agent.
At sagittal reconstructions of a control CT of 2 years later, we appreciate that the hematoma has encapsulated and instead of the original right kidney, there is a transplanted kidney. The patient due to his acquired cystic kidney needed an allograft.
WS after spontaneous, non-traumatic kidney cyst rupture is a rare entity. The WS is a potentially life-threatening condition.
The treatment applied in retroperitoneal bleeding depends on its causes and intensity. The results of scan examination, such as diagnostic ultrasonography and CT, are decisive in this respect. Nephrectomy may be recommended if a tumor is identified. Also in any other situation entailing intensive bleeding, and when the general condition is not stable, it is necessary to perform surgical intervention or selective embolization–like in our case-.
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2. Another similar case in a 54-year-old man who consulted for the pain of the renal colic type and hemodynamic instability. The urgent CT showed a retroperitoneal hematoma on the right side and right hemoperitoneum extended to the pelvic cavity, that it seemed to have a renal origin. Reviewing his previous imaging techniques, there was abdominal sonography where a simple cyst was viewed in the lower right kidney pole 3 years ago. The features of CT and US help us to affirm it is a WS for probably spontaneous rupture of the cyst.
After that, arteriography was performed where an aneurysmatic dilatation is seen in renal hilum with contrast extravasation in the lower pole. Subsequently, it is embolized with a sclerosing agent.
At sagittal reconstruction of a control CT of 6 months later, we appreciate the hematoma has encapsulated and the coils, as well.
Some predisposing factors for spontaneous rupture of cyst have been identified such as:
- Urinary tract infection.
- Increase of pressure inside the cyst by intracystic bleeding, hypertension o coagulation disorders.
- Increase of pressure inside the tract urinary by obstructive uropathy or lithiasis.-
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3. On the other hand, a 54-year-old with left nephrectomy due to renal cancer that at a control renal ultrasound proof it is identified a nodular image, together to a renal cyst, suspected of malignancy. For this reason, it was decided to perform a CT which confirmed the suspicion of malignancy. Subsequently, an MRI was performed. If we look at T2-weighted imaging, we appreciate a hyperintense nodular lesion that is a simple cyst. On another superior level, we see the suspected of malignancy lesion. Now, if we look at in-phase (IP) and out-of-phase (OOP) sequences, we appreciate that this lesion at IP imaging is slightly hyperintense while at OOP imaging is hypointense. These imaging findings confirm the malignity.
At ultrasound-guided radiofrequency ablation (RFA) we appreciate the cyst and the tumor.
If we compare tomographic features of first CT and a CT of 3 years later, we can see that the cyst is smaller, probably due to the retraction and partial emptying while the radiofrequency ablation.
4. A 76-year-old man in hemodialysis due to acquired cystic kidney disease. At the coronal and sagittal reconstruction of a control CT, we identified a nodular lesion (3 cm) in the upper renal sinus, apparently solid, which has increased in size concerning the previous CT. It was difficult to assess whether it was inside the excretory tract since it did not there was sufficient contrast removal by the kidneys in the elimination phase, which may be a urothelial tumor of the upper calyx. At CT of some months later, this lesion was no longer present. We think that it probably emptied spontaneously into the urinary tract and so it was benign.
5. A 72-year-old man who consulted for left pain of the renal colic type. At the coronal and sagittal reconstruction, we saw bilateral parapelvic cysts but the left cyst had thickened walls and slightly inflammatory changes. This cyst was infected. At the elimination phase, we confirmed that was a cyst and not urinoma since we did not see contrast step inside the cyst.
6. A 70-year-old man with recurrent bladder cancer. At the coronal and sagittal reconstruction of a control CT, we appreciate a right peripelvic cyst that presents an exophytic component that produces compression on the urinary tract and a discrete ectasia of upper and middle calyces.