Teaching Case

Clinical Summary: We present a case of a 40-year- old male patient complaining of vague abdominal pain of 9 month duration with no significant physical findings. Application of El Fortia Criteria; Ultrasonography was superior in identifying the hydatid cyst nature.

A 40 year old male patient presented with dull aching vague abdominal pain of 9 month duration, insidious in onset, non-progressive. There were no other symptoms associated with the pain. On physical examination, no abnormality detected and systemic examination did not reveal any substantial abdominal signs. Routine blood examinations were normal. The X-ray of the abdomen and chest were normal. Ultrasonography of the abdomen revealed a multilocular cyst located in the upper pole of the left kidney measuring 6.4 X 7.0X 6.6 cm in diameter (Fig, 1a). Application of the WSC by magnification of the internal septa showed double layers representing walls of two daughters lying contiguous to each other [i.e Positive Daughter-Wall Sign - DWS], (Fig, 1b). On IVU, a filling defect was demonstrated, in the nephrogram phase on the left side and was not communicating with the calyceal system. An enhanced CT scan of the abdomen displayed a multilovesicular cystic formation located at the upper pole of the left kidney with no similar cysts seen in other abdominal viscera. A diagnosis of Isolated Renal Echinococcosis was made. The cyst was removed surgically and the patient was put on a pre-operative course of medical therapy Histopathology confirmed the diagnosis of a hydatid cyst. Post-operative follow-up of the patient for one year has shown the patient to be Cystic Hydatid Disease free.

Kidney hydatid cyst is an acquired disease caused by the parasite echinococcus granulosis. Renal echinococcosis comprises about 2% of all hydatid disease in man [1]. Two variants of the disease occur, Classic hydatid disease caused by relatively benign echinococcus granulosus and the rarer [2] multilocular variant caused by echinococcus multilocularis or alvularis, which is more aggressive because it infiltrates the organ involved and hence can not be easily removed. The embryos of echinococcal granulosis migrate into the small bowel wall to enter the mesenteric circulation and are filtered in the liver or the lungs or the kidney, where the embryo becomes a small vesicle with an inner germinal epithelium called the laminated membrane or ectocyst. The surrounding parenchyma gets defensive reactive thickening to form a pericyst or adventitia. These two layers can be displayed on Ultrasonography result in the so called the WSC [3]. The patients usually present with vague pain in the lumbar region [4]. Radiography may identify an occasional calcified cyst. Conventional Ultrasound utilizing the pathgnomonic WSC is superior in identifying Hydatid cysts among other non-hydatic in nature [3]. CT scan is superior in localization of the lesion and may demonstrate a floating membrane, which confirms the diagnosis. Intravenous urogram is helpful to rule out a communication with renal calyceal system. Management is mainly surgery to avoid the catastrophic complications following a cyst rupture. Conservative management with oral Albendazole is unreliable being successful in only 40% of cases. Radiological intervention in the form of Percutaneous Aspiration Injection Re-aspiration followed by Percutaneous drainage (PAIR-PD) [6], has been described [7], but is again successful in only 70% of cases of unilocular cysts. Hence, surgery is the main form of treatment especially for the multilvesicular variant of the disease. No intervention is needed when the cyst walls are calcified [8]. In our case, the diagnosis of Echinococcal cyst was confirmed utilizing the very simple the WSC ( El Fortia Criteia ). However, partial nephrectomy was successfully performed followed by a course of oral postoperative Albendazole.