Ruptured renal hydatid cyst

Case contributed by Husam Hussein Yaseen
Diagnosis almost certain


Left-sided loin pain for four days.

Patient Data

Age: 45 years
Gender: Male

An abdominal CT scan reveals a complex cystic lesion at the lower pole of the left kidney with a hyperdense wall and no noticeable enhancement in the post-contrast study. The parenchymal portion of the cyst wall is ill-defined, and the cyst looks in continuity with some calyces that result in mild left-sided hydronephrosis with upper ureteric dilatation. The delayed scan show leakage of contrast to the peri-pelvic region feature suggestive of intra-calyceal rupture of renal hydatid cyst with renal pelvis tear.


The left kidney ultrasound scan shows a unilocular non-vascular cystic lesion with daughter cysts inside and a thick capsule (that casts a lateral shadow). A direct connection of the cyst with the renal calyces was noticed.

Case Discussion

Renal hydatid disease is rare (3% of cases), usually solitary and located in the cortex. These patients may present with a flank mass, dysuria, pyuria, hematuria, persistent fever, renal stones, hypertension or renal colic. Hydatiduria can occur after the rupture of the cyst into the collecting system. Any form of hydatid cyst can be seen in renal hydatid disease. Mural calcification and daughter cysts are often coexistent. These findings are helpful in the differential diagnosis of a hydatid cyst from a simple renal cyst, necrotic renal cell carcinoma, renal abscess and infected cysts. Still, it sometimes can be difficult to differentiate a hydatid cyst from necrotic renal cell carcinoma since calcifications may be encountered in both lesions 1.

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