Renal hydatid infection is a very rare manifestation of hydatid disease.
For a general discussion, and for links to other system specific manifestations, please refer to the article on hydatid disease.
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Epidemiology
Renal hydatid infection is seen in less than 5% of patients with hydatid disease 1.
Clinical presentation
Clinical manifestations are variable and have polymorph symptomatology, which is rarely specific. 3. Hydaturia is a pathognomonic sign of renal hydatidosis and results from the rupture of a hydatid cyst into the collecting system 1. Hydaturia is seen in only 10-20% of renal hydatidosis and is often microscopic. Macroscopic hydaturia may also observed rarely 4.
Pathology
A parasitic zoonosis with the Echinococcus tapeworm causes infection. The kidneys are the most commonly affected urinary organs, but bladder, prostate, seminal vesicles and testis can also be involved 2.
Radiographic features
Plain radiograph
The plain x-ray may show a soft-tissue mass or a ring-shaped calcification in the renal region.
Excretory urography
May demonstrate caliceal distortion, caliectasis and a non-functioning kidney, possibly caused by the mass effect of cystic lesions.
Ultrasound
May show anechoic lesions with well-defined margins.
CT
CT is more accurate and sensitive 2 and shows unilocular or multilocular cysts with or without peripheral calcifications 1. CT may also show a detached membrane, a multiloculated cyst with mixed internal density, and daughter cysts with lower density than the maternal matrix 2.
It should reminded that if a renal hydatid cyst presents as a multiseptate cystic renal lesion, the Bosniak classification shouldn't be used because the renal cyst-like lesions with infectious, inflammatory and vascular etiology are not classified with the Bosniak system 5.
Treatment and prognosis
The surgical approach remains the treatment of choice; particularly using laparoscopy and the resection should be mostly conservative 3.