A case report of renal hydatid cyst

Abstract

Hydatidosis (hydatic cyst) is one of the most important common infectious diseases between humans and animals, which is transmitted through parasite eggs (worms).

A band (of the Echinococcus family) is caused by Echinococcus granulosus larvae, which randomly infects a person with one or more cysts.

Hydatid cyst affects all organs. The most common sites of involvement include the liver, lung, and rarely in the kidney, brain.

It can also cause heart, bone and spleen.

Considering the rarity of hydatid cyst in the kidney, this article introduced a 14-year-old patient with hydatid cyst of the kidney.

1 Introduction

Hydatid cyst is one of the most important zoonosis diseases, which is caused by Echinococcus cestode, especially Echinococcus granulosus. Canids are the final hosts and herbivores are the intermediate hosts of the parasite. Man is the accidental host of this parasite. Human infection is through the oral-fecal route and is caused by eating vegetables contaminated with dog feces containing parasite eggs. After eating, the eggs are opened in the intestinal tract and enter the intestine through the mucus and enter the bloodstream. The disease also occurs in direct contact with dogs. Animal fodder control, careful inspection of meat before entering the market, freezing meat at minus 18 and cooking it at 50° can prevent the occurrence of this infection in the community. The disease is common in different regions of the world where animal husbandry is common, such as the Mediterranean countries, the Middle East, Australia and New Zealand. Hydatid disease commonly affects 50–70 % of the liver and 20–30 % of the lungs. But sometimes it is rarely formed in other organs such as the heart, breast, soft tissue of the neck and kidney. The presence of this cyst in humans may be asymptomatic, but it manifests with clinical symptoms, which in most cases is an accidental enlargement of the cyst. It is discovered during surgery. After microscopic examination of the tissue and observation of daughter cysts, which is one of the main findings of hydatid cyst, the final diagnosis is confirmed by the pathologist. Considering that this infection is common in Iran and kidney involvement is a rare site for this parasite. Hydatid cyst can be considered an important differential diagnosis in the examination of renal cysts.

2 Case presentation

A 14-year-old lady has complained of right flank pain for the past 7 months. The pain was not diffuse and was continuous. There was no hematuria, dysuria, frequency, fever, chills, weight loss, or loss of appetite. Vital signs were stable during the examination. She had only a slight thunderclap in the right flank area.

In the sonography of the patient, a cystic lesion with a fine internal echo and septation with dimensions of 25 × 46 × 60 mm can be seen in the subcapsular and perinephric space of the right kidney in the vicinity of the middle and lower bridge of this kidney, which can indicate a hydatid cyst.

You can see a CT scan of the abdomen and pelvis with and without injected contrast which is marked with an arrow( Fig. 1 A and B ).

The interesting thing about this patient was that the patient’s CT scan did not look very similar to a hydatid cyst, and the sonographer, based on the evidence in the ultrasound, suggested a differential diagnosis of a hydatid cyst for the patient.(The difference between this case report and others ).

Hydatid IgG antibody titer of the patient was 1.160, which was considered positive.

Given that the most common sites of involvement of hydatid cysts are the lungs and liver, a CT scan of the lungs was also performed, which showed no involvement. There was no liver involvement in the CT scan of the abdomen and pelvis.

Finally, the patient underwent surgery to remove the cyst. In the flank position, after cutting the skin and muscles and fascia, and after carefully releasing the kidney, a cyst was observed in the anterior part of the kidney. As it was said in the ultrasound and CT scan, the cyst was in the subspace. It was capsular and did not originate from the kidney parenchyma and was completely separate from the kidney.

The surrounding of the kidney and the cyst were placed in the retroperitoneal space with gas soaked with hypertonic saline (2 %). ( To prevent the cyst contents from spreading and causing anaphylactic shock, we placed a gauze soaked in hypertonic saline around the kidney and cyst). Hypertonic saline was injected into the cyst and after 30 minutes the contents of the cyst were suctioned. The cyst was completely drained and the space inside the cyst was washed again with hypertonic saline. The cyst wall and its contents, which included girl cysts, were sent for pathology( Fig. 2A and B&2 C ).