|Home | About | Journals | Submit | Contact Us | Français|
Human hydatid disease is known since ancient times and has worldwide distribution . Caused mostly by Echinococcus granulosis, rarer forms are attributed to Echinococcus alveolaris. In humans approximately two thirds of the cysts occur in the liver, 25% in the lungs and 5-10% are distributed through the peripheral arterial system to various sites . We present an unusual case of recurrent hydatid cyst which presented as a retroperitoneal mass.
A 81 year old ex-serviceman presented with a slowly enlarging right flank mass of 8 years duration. It was associated with a dull ache since one year. There were no bowel or urinary symptoms. The patient gave history of operative intervention for a right loin swelling in 1964. General examination revealed a well built male with no remarkable findings. The abdomen bore two scars of previous operations which the patient claimed were made at the same sitting. One was a transcostal 12th rib approach in the right flank, the other was a 30 cm long incision from the right renal angle till the suprapubic region. There was a large incisional hernia along the length of the incisions. A firm lobulated retroperitoneal swelling was palpable from the right hypochondrium till the iliac fossa. A plain radiograph revealed an irregular calcified mass in the right flank. On ultrasonography there were multiple cystic masses in the right lumbar and iliac regions, the largest measuring 74x58mm (Fig-1). Layering was seen in the dependant portions. There was a small hypoechoeic lesion seen in the right lobe of liver posteriorly. Kidneys were normal and no other abdominal pathology was detected. Relevant biochemical and haematological parameters were normal.
On a diagnosis of retroperitoneal hydatidosis the patient was put on tablet Albendazole 10 mg/kg/day for four weeks and taken up for laparotomy thereafter.
A retroperitoneal flank approach was made after excising the previous scar. There were multiple cysts extending from the inferior pole of right kidney till the iliac fossa. The cysts were extensively adherent to the posterior abdominal wall, femoral nerve and iliac bone with medial encroachment till the inferior vena cava. Due to dense infiltration and vascular adhesions to important structures complete excision of the cysts was not considered feasible. The area was isolated with 5% povidone iodine packs (Fig-2). The largest cysts were aspirated and irrigated with povidone. Most cyst contents were thick with sediment. The cyst walls were excised as completely as possible and operative field thoroughly irrigated with povidone iodine. No peritoneal or renal involvement was evident. The incisional hernia was repaired along the extent of the incision made. To limit morbidity no attempt was made to dissect and repair the superior extent of the hernia. Post operative period was uneventful and the patient was continued on Albendazole for further 4 weeks (Fig-3). The patient has been given 3 cycles of Albendazole therapy thereafter and is asymptomatic on follow up at 2 years with no recurrence.
Hydatid disease is caused by the cestode Echinococcus granulosis. The adult worm resides in canines and its ova are shed in the faecal matter. Intermediate hosts are usually sheep and accidental ingestion occurs in man whereupon the embryos penetrate the intestinal mucosa and enter portal circulation. 90% are trapped in the liver and lungs but some may spread via the systemic circulation. Primary cysts comprise, 3 walls around a fluid cavity. Rupture results in daughter cysts developing from germinal epithelium. Secondary implantation may occur after spillage into adjacent cavities and was possible in our case. The vast majority of abdominal and pelvic cysts are considered secondary to prior hepatic localisation following spontaneous rupture or surgical inoculation . A lymphatic route could also lead the larvae from the intestinal lymph vessels to the thoracic channel and anywhere in the body . Retroperitoneal locations of hydatid cysts are rare even in endemic areas and are defined as those in retroperitoneal space but independent of the organs confined therein. In a 28 year survey in Greece there were only 2 cases of retroperitoneal hydatid disease . Recurrent cysts in the retroperitoneum are extremely rare with isolated reports in literature and could represent postoperative seeding .
The disease profile in our case posed a dilemma. The patient had initially presented in 1964 with a painless right loin swelling. The two incisions given at the same sitting suggest an initial diagnosis and approach for a possible renal pathology. Revision of incision indicates the possibility of a lesion in the posterior segment of right lobe of liver with retroperitoneal extension or implantation . A primary hydatid of retroperitoneum also needs consideration . During the present evaluation ultrasonography revealed a small hypoechocic lesion in the right liver lobe which may have been the site of primary disease. Multivesicular thin walled cysts with hydatid sand on sonography was pathognomic. The surgical approach is rarely specified in literature and in our case an extraperitoneal flank approach was employed. This had the benefit of avoidance of risk of peritoneal spillage and also permitted repair of the incisional hernia.
Surgical excision is usually difficult due to strong adhesions to surrounding structures and carries the risk of anaphylaxis from spillage of the cyst contents . Retroperitoneal cysts are also associated with dense vascular adhesions to the surrounding organs . Complete removal is thus not possible due to extensive infiltration of important structures [3, 10]. In our case the cyst was adherent to the inferior vena cava and femoral nerve. Hence evacuation of the contents with partial pericystectomy was done. Thorough irrigation of the operative field with povidone iodine was done followed by 4 weeks of Albendazole therapy. The patient is free of recurrence at follow up after 2 years. The extensive recurrence in this case after the initial operation possibly occurred due to the initial undiagnosed nature of the disease pathology. Non availability of scolicidal agents would also be a contributory factor. With advancements in diagnosis, medical and surgical management it is unlikely that one would face similar extensive recurrence in future.