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Isolated Renal Hydatidosis: Experience With 20 Cases
0022-5347/03/1691-0186/0 THE JOURNAL OF UROLOGY® Copyright © 2003 by AMERICAN UROLOGICAL ASSOCIATION
Vol. 169, 186 –189, January 2003 Printed in U.S.A.
DOI: 10.1097/01.ju.0000042277.16553.5c
ISOLATED RENAL HYDATIDOSIS: EXPERIENCE WITH 20 CASES ˘ ATAY GO ¨G ˘U ¨ S¸, MUT S¸AFAK, SU ¨ MER BALTACI C ¸ AG
AND
¨ RKO ¨ LMEZ KADIR TU
From the Department of Urology, Ankara University, School of Medicine, Ankara, Turkey
ABSTRACT
Purpose: Cystic hydatidosis is an endemic disease caused by the larval form of Echinococcus granulosus. It is mostly evident in the liver and lungs, and renal hydatidosis is uncommon. Renal hydatidosis is usually associated with other organ involvement and isolated disease is extremely rare. We present our experience with isolated renal hydatidosis in 20 patients. Materials and Methods: The charts of 20 patients with isolated renal hydatidosis who were hospitalized in our department during a 25-year period were reviewed retrospectively. The clinical, laboratory and radiologic diagnosis, and treatment of these cases are discussed. Results: The main clinical symptom was lumbar pain. There was no specific or pathognomonic laboratory test for renal hydatidosis except hydaturia, which was present only in 1 patient (5%). Of radiologic examinations computerized tomography had the highest sensitivity and specificity. Treatment was mainly surgical. We performed nephrectomy in 13 patients, and cystectomy and marsupialization in 6. One patient refused all treatments. There was no postoperative morbidity or mortality. Conclusions: Isolated renal hydatidosis is extremely rare. The main problem is the correct preoperative diagnosis. Although radiologic studies and serological-immunological tests support the diagnosis of hydatid disease, a correct preoperative diagnosis is not always easy. The treatment is mainly surgical, and with appropriate diagnosis and treatment the prognosis is good. KEY WORDS: kidney, echinococcosis, back pain, infection
Cystic hydatic disease is a parasitic infestation caused by the larval form of Echinococcus granulosus. It is endemic in parts of Africa, Latin America, Mediterranean, the southeast1–3 and Turkey,4, 5 and it is related to close contact with dogs, sheep and cattle. Humans are intermediate hosts for hydatic cysts.6 Hydatic cysts are mostly evident in the liver and lungs, while renal involvement is rare, comprising only 2% to 4% of all cases.6, 7 The kidneys are the most commonly affected organs in the genitourinary tract but hydatic cyst of the prostate, bladder, seminal vesicles and testis have been also reported.8 Echinococcal larvae may reach the kidneys through the bloodstream, lymph glands or by direct invasion.6 The kidney is usually involved as part of disseminated disease and isolated renal echinococcus is uncommon. We present our experience with 20 patients with isolated renal hydatidosis who were hospitalized and treated at our department during a 25-year period. MATERIALS AND METHODS
A total of 20 patients with isolated renal hydatidosis were hospitalized and treated at our department between 1977 and 2001. The medical records of these patients were retrospectively reviewed. Diagnostic and therapeutic procedures are discussed. Investigations included a history, physical examination, complete blood count, serum biochemistry, urinalysis, the Casoni (intradermal skin test) and Weinberg (complement fixation test) tests, indirect hemagglutination test and immunoelectrophoresis. Patients also underwent radiologic evaluation with plain x-ray, excretory urography (IVP), ultrasonography and computerized tomography (CT). All patients underwent surgery and pathological examination revealed renal hydatidosis. Accepted for publication on August 30, 2002.
RESULTS
Mean patient age was 30.5 years (range 11 to 57). Of the 20 patients 10 were male and 10 were female (male-to-female ratio 1:1). A total of 12 patients lived in rural areas and were farmers, while the others had various occupations. The hydatic cyst was on the left side in 14 cases and on the right side in 6. The main clinical symptom was lumbar pain, which was present in 16 patients. In addition, 5 patients had a palpable mass, 2 had fever and 2 had nausea and vomiting, while a hydatic cyst was diagnosed incidentally in 2. Laboratory tests revealed eosinophilia in 6 (30%) patients, pyuria in 5 and hematuria in 4. Only 1 patient (5%) with a communicating hydatic cyst had hydaturia. The Casoni skin test was positive in 3 of 14 cases (21%). Hemaglutinationinhibition serology performed in 10 patients was positive in 6 (60%). Immunoelectrophoresis in the last 3 patients was positive in 2 (66%). Plain abdominal x-ray revealed a ring-shaped amorphous or curvilinear calcification in only 4 cases (20%) (fig. 1). IVP in 16 patients demonstrated a space occupying lesion, caliceal distortion and caliectasia in 7 (44%), and a nonfunctioning kidney in 4 (25%). Ultrasonography was useful for detecting asymptomatic cases. A complex cystic appearance was observed in 11 of 15 patients (73%). Three patients (20%) had an anechoic cyst with a uniformly thick wall and in 4 a typical honeycomb appearance was the result of the separation of the germinative membrane from the pericyst. CT in 12 cases provided more details than ultrasonography. Daughter cysts and multivesicular cystic structures were noted in 6 (50%) patients (figs. 2 and 3). Magnetic resonance imaging in 2 patients did not add any special findings to CT to aid in the diagnosis. Of the 20 cases 19 were treated surgically. We performed nephrectomy in 13 patients, and cystectomy and marsupialization in 6. A single patient refused all treatments. In 1 case
186
187
ISOLATED RENAL HYDATIDOSIS
FIG. 3. CT shows small hydatid cyst on left kidney
DISCUSSION
FIG. 1. Plain x-ray reveals curvilinear calcifications
FIG. 2. CT demonstrates hydatid cyst of right kidney with mixed density and peripheral calcifications.
the hydatic cyst ruptured spontaneously into the retroperitoneal region and a perinephritic abscess developed. Scolices were detected while draining the abscess during surgery. Pathological examination in all patients revealed renal hydatidosis. There was no operative or postoperative mortality and all patients remained well.
Hydatic cyst is a parasitic infestation caused by the larval form of Echinococcus granulosus. The adult worm of Echinococcus granulosus is present in the small intestine of dogs. Echinococcal eggs excreted in the feces of dogs are ingested by intermediate hosts. Humans are also intermediate hosts for echinococcal cysts. Infection occurs by contact with dogs carrying embryonic eggs. Ingested eggs hatch in the duodenum, penetrate the intestinal mucosa and then enter the portal system.6 Hydatidosis can be present in all parts of the human body but urinary tract involvement is uncommon. The most affected organs are the liver and lungs, and renal involvement develops only in 2% to 4% of all cases.6, 7 Most affected patients are between the third and fifth decades of life,7 and renal hydatidosis in children is rare.6, 9 Although the kidney is the most affected site in the urinary tract, hydatic cyst of the prostate, bladder and epididymis has been also reported.8 Echinococcal larvae may reach the kidneys through the bloodstream, lymph glands or by direct inoculation.7 Renal invasion is mostly due to a secondary manifestation of the disease and isolated renal echinococcus is extremely rare. In our series we present 20 cases of isolated renal hydatidosis, which is one of the largest series in the literature. There are no specific signs or symptoms for renal hydatidosis and the disease usually remains asymptomatic for years. The most common symptoms are palpable mass, flank pain, hematuria, malaise, fever and hydaturia.2, 3, 6 Complications of hydatic cyst, such as infection, abscess, hemorrhage, necrosis and obstruction of the pelvicaliceal system, are also present in some cases.6 None of these symptoms are specific for renal hydatidosis except hydaturia. In our series the main clinical symptom was lumbar pain, which was present in 16 patients (80%). Hydaturia is a pathognomonic sign. It involves passage of a typically grape-like material in the urine, which results from rupture of the cyst into the collecting system. Although it is pathognomonic, it has been reported in 5% to 25% of all renal hydatidosis cases.5, 6 Hydaturia was detected only in 1 patient (5%) in our study with a communicating renal hydatic cyst. There is no serological or immunological test pathognomonic for hydatid disease. Eosinophilia, the Casoni (intradermal skin) and Weinberg (complement fixation) tests, and indirect hemagglutination test may be helpful for diagnosing renal hydatidosis.10 These tests reflect overall sensitivity to the hydatid antigen prepared from isolated hydatid cyst fluid.11 Eosinophilia is detected in 20% to 50% of patients with renal hydatid disease.5, 8 The poor efficacy of eosinophilia is
188
ISOLATED RENAL HYDATIDOSIS
due to a high incidence of false-positive results with other parasitic infestations.1, 2 The Casoni skin test produces positive results in about 25% to 50% of patients,5, 6, 8 while the Weinberg test yields about 40% positive results.5, 8 Although the indirect hemagglutination test has a higher positive rate of about 75% for hydatid disease,6, 10 it also shows falsenegative results due to circulating immune complexes and false-positive data due to cross-reactivity with other parasitic infections, such as schistosomiasis and cysticercosis.10 It should be concluded that negative serology does not exclude hydatid disease and positive serology does not confirm the diagnosis. When these tests are positive, it may be helpful to suggest obtaining further information on hydatid disease but there is no correlation with the pathological stage of renal hydatid disease.5 In our series the indirect hemagglutination test had the highest sensitivity for hydatidosis compared with eosinophilia and the Casoni-Weinberg tests. We have not performed the latter 2 tests for diagnosing hydatid disease at our department for 5 years. Recently counter immunoelectrophoresis against arch-5 gained wide acceptance with higher specificity and sensitivity rates.6, 11 Angulo et al reported 100% positive results with counter immunoelectrophoresis against arc-5 in 7 patients.6 In our series 2 of 3 patients showed positive results for renal hydatidosis on immunoelectrophoresis. Therefore, we think that in the future counter immunoelectrophoresis would gain more acceptance as a serological test for diagnosing hydatid disease due to its higher sensitivity and specificity. At that point we believe that the indirect hemagglutination test and counter immunoelectrophoresis would be sufficient as serological tests for diagnosing renal hydatidosis. However, further studies in a large number of patients are needed to confirm this suggestion. Radiological studies have a more important place in the preoperative diagnosis of renal hydatic disease. On plain x-ray ring-shaped or peripheral curvilinear calcifications can be visualized6, 7, 12 but they are nonspecific. Calcifications are mostly linear but multilaminated or amorphous calcifications can also be observed.6 In a large series of patients with calcified renal masses only 0.9% had renal hydatidosis at 10 years of followup.13 Studies in the literature show calcifications on plain x-ray in 62% of patients,6 although in our series only 5 (25%) showed calcifications on plain x-ray. IVP reveals mostly distortion of the calixes or caliceal ectasia as a result of a renal mass involving the collecting system. A nonfunctioning kidney or a filling defect in the renal pelvis may rarely be evident on IVP.6, 12 Today ultrasound and CT are usually performed for the preoperative diagnosis of hydatid disease with higher specificity and sensitivity. Ultrasonography is usually the primary radiologic investigation with the advantages of costeffectiveness and noninvasiveness. Ultrasonography usually demonstrates the typical appearance of an echinococcal cyst.14 This cyst form may be unilocular or multivesicular.6, 14 The determination of daughter cysts, which is characteristic of hydatid disease, is also possible on ultrasonography.14 Of radiologic investigations CT has some advantages. CT can more easily detect calcifications and daughter cysts, and it is more sensitive and accurate than ultrasonography.5, 14, 15 Also, CT provides more detailed information about communication with the urinary tract and extrarenal disease.6, 14 Magnetic resonance imaging was performed in some studies but it has no advantages over CT,16 as in our 2 cases. Retrograde pyelography may be helpful for showing the renal pelvis and cyst communication clearly, and differentiate communicating and noncommunicating cysts.10 We did not use retrograde pyelography for the diagnosis in any patient. Treatment for renal echinococcus is mainly surgical. Total or partial nephrectomy is the treatment of choice. Enucleation, marsupialization and cystectomy have been also described.6, 17 If the preoperative diagnosis involves iso-
lated disease, the retroperitoneal approach should be preferred to avoid disseminating the disease into the peritoneal cavity. The transperitoneal approach can be used in patients with extrarenal involvement. In patients with an unclear preoperative diagnosis radical nephrectomy should be performed. As do others, we also believe that partial nephrectomy causes a risk of dissemination of disease. Thus, total nephrectomy was the preferred treatment in our cases. Intraoperative spillage of the cyst may cause many serious complications, including allergic reactions, anaphylaxia and even death. The kidney should be packed with betadine soaked sponges and the cyst cavity should be filled with scolecidal agents, especially in complicated cases. Preoperative albendazole therapy can be administered in cases suspicious for spillage. As scolecidal agents, 30% sodium chloride, 2% formalin, 1% iodine or 0.5% silver nitrate solutions can be used.8 We prefer to use 2% formalin solution, although it has irritative effects on the surgical team. Hydatid disease is a systemic disorder that affects many organs, such as the liver, lungs, brain and kidney. The anthelmintic agent albendazole can be used in patients with systemic disease but the overall success rate is about 25%.18 Our patients had only isolated renal hydatidosis and they did not have systemic disease. Because none of our patients had received systemic therapy or had recurrence, we believe that surgery alone is the best choice. In the literature some groups describe using anthelmintic therapy with albendazole or mebandazole postoperatively to prevent recurrence,9 but there are inadequate data to support the effectiveness of these drugs. In addition, in such cases it should also be remembered that these drugs have many serious side effects, such as hepatotoxicity, abnormal liver function test results, gastrointestinal symptoms, allergic reactions, leukopenia and alopecia.18 Recently some groups recommended percutaneous management for renal hydatidosis.19, 20 Goel et al performed percutaneous treatment in 4 patients and preserved 3 of 4 renal units.19 They concluded that percutaneous drainage of renal hydatic disease is a safe method associated with a short hospital stay. We believe that this treatment modality carries the risk of dissemination and fatal anaphylactic reactions. We think that further studies in more patients would clarify the usefulness of this technique in renal hydatidosis surgery. CONCLUSIONS
Although isolated renal hydatidosis is uncommon, it should be considered in the differential diagnosis of solid renal masses, especially in suspicious cases. The main treatment is surgery. With appropriate diagnosis and treatment the prognosis is good. REFERENCES
1. Halim, A. and Vaezzadeh, K.: Hydatic disease of the genitourinary tract. Br J Urol, 52: 75, 1980 2. Saidi, F.: Hydatid cysts of the kidney. In: Surgery of Hydatid Disease. Philadelphia: W. B. Saunders Co., chapt. 7, p. 332, 1976 3. Horchani, A., Yassine, N., Kbaier, I., Attyaoui, F. and Zribi, A. S.: Hydatid cyst of the kidney. A report of 147 controlled cases. Eur Urol, 38: 461, 2000 4. Gogus, O., Beduk, Y. and Topukcu, Z.: Renal hydatid disease. Br J Urol, 68: 466, 1991 5. Afsar, H., Yag˘ ci, F., Meto, S. and Aybasti, N.: Hydatic disease of the kidney: evaluation and features of diagnostic procedures. J Urol, 151: 567, 1994 6. Angulo, J. C., Sanchez-Chapado, M., Diego, A., Escribano, J., Tamayo, J. C. and Martin, L.: Renal echinococcus: clinical study of 34 cases. J Urol, 157: 787, 1997 7. Aragona, F., DiCandio, G., Serrata, V. and Fiorentini, L.: Renal
ISOLATED RENAL HYDATIDOSIS
8. 9. 10. 11.
12. 13.
hydatid disease: report of 9 cases and discussion of urologic diagnostic procedures. Urol Radiol, 6: 182, 1984 Buckley, R. J., Smith, S., Herschorn, S., Comisarow, R. H. and Barkin, M.: Echinococcal disease of the kidney presenting as a renal filling defect. J Urol, 133: 660, 1985 Tryfonas, G. J., Avtzoglou, P. P., Chaidos, C., Zioutis, J., Gavopoulos, S. and Limas, C.: Renal hydatid disease: diagnosis and treatment. J Pediatr Surg, 28: 228, 1993 Shetty, S. D., Al-Saigh, A. A., Ibrahim, A. I., Malatani, T. and Patil, K. P.: Hydatid disease of the urinary tract: evaluation of diagnostic methods. Br J Urol, 69: 476, 1992 Babba, H., Messedi, A., Masmoudi, S., Zribi, M., Grillot, R., Ambriose-Thomas, P. et al: Diagnosis of human hydatidosis: comparison between imaginery and six serologic techniques. Am J Trop Med Hyg, 50: 64, 1994 Hertz, M., Zissin, R., Dresnik, Z., Morag, B., Itzchak, Y. and Jonas, P.: Echinococcus of the urinary tract: radiologic findings. Urol Radiol, 6: 175, 1984 Daniel, W. W., Jr., Hartmann, G. W., Witten, D. M., Farrow, G. M. and Kelalis, P. P.: Calcified renal masses. A review of ten years experience at the Mayo Clinic. Radiology, 103: 503, 1972
189
14. Odev, K., Kilinc, M., Arslan, A., Aygun, E., Gungor, S., Durak, A. C. et al: Renal hydatid cysts and the evaluation of their radiologic images. Eur Urol, 30: 40, 1996 15. Kalavidouris, A., Pissiotis, C., Pontifex, G., Gouliamos, A., Pentea, S. and Papavassilou, C.: CT characterization of multivesicular hydatid cysts. J Comput Assist Tomogr, 10: 428, 1986 16. Morris, D. L., Buckley, R., Gregson, R. and Worthington, B. S.: Magnetic resonance imaging in hydatid disease. Clin Radiol, 38: 141, 1985 17. Poulios, C.: Echinococcal disease of the urinary tract: review of the management of 7 cases. J Urol, 145: 924, 1991 18. Von Sinner, W. N., Hellstro¨ m, M., Kagevi, I. and Norlen, B. J.: Hydatid disease of the urinary tract. J Urol, 149: 577, 1993 19. Goel, M. C., Agarwal, M. R. and Misra, A.: Percutaneous drainage of renal hydatid cyst: early results and follow-up. Br J Urol, 75: 724, 1995 20. Baijal, S. S., Basarge, N., Srinadh, E. S., Mittal, B. R. and Kumar, A.: Percutaneous management of renal hydatidosis: a minimally invasive therapeutic option. J Urol, 153: 1199, 1995
Vol. 169, 186 –189, January 2003 Printed in U.S.A.
DOI: 10.1097/01.ju.0000042277.16553.5c
ISOLATED RENAL HYDATIDOSIS: EXPERIENCE WITH 20 CASES ˘ ATAY GO ¨G ˘U ¨ S¸, MUT S¸AFAK, SU ¨ MER BALTACI C ¸ AG
AND
¨ RKO ¨ LMEZ KADIR TU
From the Department of Urology, Ankara University, School of Medicine, Ankara, Turkey
ABSTRACT
Purpose: Cystic hydatidosis is an endemic disease caused by the larval form of Echinococcus granulosus. It is mostly evident in the liver and lungs, and renal hydatidosis is uncommon. Renal hydatidosis is usually associated with other organ involvement and isolated disease is extremely rare. We present our experience with isolated renal hydatidosis in 20 patients. Materials and Methods: The charts of 20 patients with isolated renal hydatidosis who were hospitalized in our department during a 25-year period were reviewed retrospectively. The clinical, laboratory and radiologic diagnosis, and treatment of these cases are discussed. Results: The main clinical symptom was lumbar pain. There was no specific or pathognomonic laboratory test for renal hydatidosis except hydaturia, which was present only in 1 patient (5%). Of radiologic examinations computerized tomography had the highest sensitivity and specificity. Treatment was mainly surgical. We performed nephrectomy in 13 patients, and cystectomy and marsupialization in 6. One patient refused all treatments. There was no postoperative morbidity or mortality. Conclusions: Isolated renal hydatidosis is extremely rare. The main problem is the correct preoperative diagnosis. Although radiologic studies and serological-immunological tests support the diagnosis of hydatid disease, a correct preoperative diagnosis is not always easy. The treatment is mainly surgical, and with appropriate diagnosis and treatment the prognosis is good. KEY WORDS: kidney, echinococcosis, back pain, infection
Cystic hydatic disease is a parasitic infestation caused by the larval form of Echinococcus granulosus. It is endemic in parts of Africa, Latin America, Mediterranean, the southeast1–3 and Turkey,4, 5 and it is related to close contact with dogs, sheep and cattle. Humans are intermediate hosts for hydatic cysts.6 Hydatic cysts are mostly evident in the liver and lungs, while renal involvement is rare, comprising only 2% to 4% of all cases.6, 7 The kidneys are the most commonly affected organs in the genitourinary tract but hydatic cyst of the prostate, bladder, seminal vesicles and testis have been also reported.8 Echinococcal larvae may reach the kidneys through the bloodstream, lymph glands or by direct invasion.6 The kidney is usually involved as part of disseminated disease and isolated renal echinococcus is uncommon. We present our experience with 20 patients with isolated renal hydatidosis who were hospitalized and treated at our department during a 25-year period. MATERIALS AND METHODS
A total of 20 patients with isolated renal hydatidosis were hospitalized and treated at our department between 1977 and 2001. The medical records of these patients were retrospectively reviewed. Diagnostic and therapeutic procedures are discussed. Investigations included a history, physical examination, complete blood count, serum biochemistry, urinalysis, the Casoni (intradermal skin test) and Weinberg (complement fixation test) tests, indirect hemagglutination test and immunoelectrophoresis. Patients also underwent radiologic evaluation with plain x-ray, excretory urography (IVP), ultrasonography and computerized tomography (CT). All patients underwent surgery and pathological examination revealed renal hydatidosis. Accepted for publication on August 30, 2002.
RESULTS
Mean patient age was 30.5 years (range 11 to 57). Of the 20 patients 10 were male and 10 were female (male-to-female ratio 1:1). A total of 12 patients lived in rural areas and were farmers, while the others had various occupations. The hydatic cyst was on the left side in 14 cases and on the right side in 6. The main clinical symptom was lumbar pain, which was present in 16 patients. In addition, 5 patients had a palpable mass, 2 had fever and 2 had nausea and vomiting, while a hydatic cyst was diagnosed incidentally in 2. Laboratory tests revealed eosinophilia in 6 (30%) patients, pyuria in 5 and hematuria in 4. Only 1 patient (5%) with a communicating hydatic cyst had hydaturia. The Casoni skin test was positive in 3 of 14 cases (21%). Hemaglutinationinhibition serology performed in 10 patients was positive in 6 (60%). Immunoelectrophoresis in the last 3 patients was positive in 2 (66%). Plain abdominal x-ray revealed a ring-shaped amorphous or curvilinear calcification in only 4 cases (20%) (fig. 1). IVP in 16 patients demonstrated a space occupying lesion, caliceal distortion and caliectasia in 7 (44%), and a nonfunctioning kidney in 4 (25%). Ultrasonography was useful for detecting asymptomatic cases. A complex cystic appearance was observed in 11 of 15 patients (73%). Three patients (20%) had an anechoic cyst with a uniformly thick wall and in 4 a typical honeycomb appearance was the result of the separation of the germinative membrane from the pericyst. CT in 12 cases provided more details than ultrasonography. Daughter cysts and multivesicular cystic structures were noted in 6 (50%) patients (figs. 2 and 3). Magnetic resonance imaging in 2 patients did not add any special findings to CT to aid in the diagnosis. Of the 20 cases 19 were treated surgically. We performed nephrectomy in 13 patients, and cystectomy and marsupialization in 6. A single patient refused all treatments. In 1 case
186
187
ISOLATED RENAL HYDATIDOSIS
FIG. 3. CT shows small hydatid cyst on left kidney
DISCUSSION
FIG. 1. Plain x-ray reveals curvilinear calcifications
FIG. 2. CT demonstrates hydatid cyst of right kidney with mixed density and peripheral calcifications.
the hydatic cyst ruptured spontaneously into the retroperitoneal region and a perinephritic abscess developed. Scolices were detected while draining the abscess during surgery. Pathological examination in all patients revealed renal hydatidosis. There was no operative or postoperative mortality and all patients remained well.
Hydatic cyst is a parasitic infestation caused by the larval form of Echinococcus granulosus. The adult worm of Echinococcus granulosus is present in the small intestine of dogs. Echinococcal eggs excreted in the feces of dogs are ingested by intermediate hosts. Humans are also intermediate hosts for echinococcal cysts. Infection occurs by contact with dogs carrying embryonic eggs. Ingested eggs hatch in the duodenum, penetrate the intestinal mucosa and then enter the portal system.6 Hydatidosis can be present in all parts of the human body but urinary tract involvement is uncommon. The most affected organs are the liver and lungs, and renal involvement develops only in 2% to 4% of all cases.6, 7 Most affected patients are between the third and fifth decades of life,7 and renal hydatidosis in children is rare.6, 9 Although the kidney is the most affected site in the urinary tract, hydatic cyst of the prostate, bladder and epididymis has been also reported.8 Echinococcal larvae may reach the kidneys through the bloodstream, lymph glands or by direct inoculation.7 Renal invasion is mostly due to a secondary manifestation of the disease and isolated renal echinococcus is extremely rare. In our series we present 20 cases of isolated renal hydatidosis, which is one of the largest series in the literature. There are no specific signs or symptoms for renal hydatidosis and the disease usually remains asymptomatic for years. The most common symptoms are palpable mass, flank pain, hematuria, malaise, fever and hydaturia.2, 3, 6 Complications of hydatic cyst, such as infection, abscess, hemorrhage, necrosis and obstruction of the pelvicaliceal system, are also present in some cases.6 None of these symptoms are specific for renal hydatidosis except hydaturia. In our series the main clinical symptom was lumbar pain, which was present in 16 patients (80%). Hydaturia is a pathognomonic sign. It involves passage of a typically grape-like material in the urine, which results from rupture of the cyst into the collecting system. Although it is pathognomonic, it has been reported in 5% to 25% of all renal hydatidosis cases.5, 6 Hydaturia was detected only in 1 patient (5%) in our study with a communicating renal hydatic cyst. There is no serological or immunological test pathognomonic for hydatid disease. Eosinophilia, the Casoni (intradermal skin) and Weinberg (complement fixation) tests, and indirect hemagglutination test may be helpful for diagnosing renal hydatidosis.10 These tests reflect overall sensitivity to the hydatid antigen prepared from isolated hydatid cyst fluid.11 Eosinophilia is detected in 20% to 50% of patients with renal hydatid disease.5, 8 The poor efficacy of eosinophilia is
188
ISOLATED RENAL HYDATIDOSIS
due to a high incidence of false-positive results with other parasitic infestations.1, 2 The Casoni skin test produces positive results in about 25% to 50% of patients,5, 6, 8 while the Weinberg test yields about 40% positive results.5, 8 Although the indirect hemagglutination test has a higher positive rate of about 75% for hydatid disease,6, 10 it also shows falsenegative results due to circulating immune complexes and false-positive data due to cross-reactivity with other parasitic infections, such as schistosomiasis and cysticercosis.10 It should be concluded that negative serology does not exclude hydatid disease and positive serology does not confirm the diagnosis. When these tests are positive, it may be helpful to suggest obtaining further information on hydatid disease but there is no correlation with the pathological stage of renal hydatid disease.5 In our series the indirect hemagglutination test had the highest sensitivity for hydatidosis compared with eosinophilia and the Casoni-Weinberg tests. We have not performed the latter 2 tests for diagnosing hydatid disease at our department for 5 years. Recently counter immunoelectrophoresis against arch-5 gained wide acceptance with higher specificity and sensitivity rates.6, 11 Angulo et al reported 100% positive results with counter immunoelectrophoresis against arc-5 in 7 patients.6 In our series 2 of 3 patients showed positive results for renal hydatidosis on immunoelectrophoresis. Therefore, we think that in the future counter immunoelectrophoresis would gain more acceptance as a serological test for diagnosing hydatid disease due to its higher sensitivity and specificity. At that point we believe that the indirect hemagglutination test and counter immunoelectrophoresis would be sufficient as serological tests for diagnosing renal hydatidosis. However, further studies in a large number of patients are needed to confirm this suggestion. Radiological studies have a more important place in the preoperative diagnosis of renal hydatic disease. On plain x-ray ring-shaped or peripheral curvilinear calcifications can be visualized6, 7, 12 but they are nonspecific. Calcifications are mostly linear but multilaminated or amorphous calcifications can also be observed.6 In a large series of patients with calcified renal masses only 0.9% had renal hydatidosis at 10 years of followup.13 Studies in the literature show calcifications on plain x-ray in 62% of patients,6 although in our series only 5 (25%) showed calcifications on plain x-ray. IVP reveals mostly distortion of the calixes or caliceal ectasia as a result of a renal mass involving the collecting system. A nonfunctioning kidney or a filling defect in the renal pelvis may rarely be evident on IVP.6, 12 Today ultrasound and CT are usually performed for the preoperative diagnosis of hydatid disease with higher specificity and sensitivity. Ultrasonography is usually the primary radiologic investigation with the advantages of costeffectiveness and noninvasiveness. Ultrasonography usually demonstrates the typical appearance of an echinococcal cyst.14 This cyst form may be unilocular or multivesicular.6, 14 The determination of daughter cysts, which is characteristic of hydatid disease, is also possible on ultrasonography.14 Of radiologic investigations CT has some advantages. CT can more easily detect calcifications and daughter cysts, and it is more sensitive and accurate than ultrasonography.5, 14, 15 Also, CT provides more detailed information about communication with the urinary tract and extrarenal disease.6, 14 Magnetic resonance imaging was performed in some studies but it has no advantages over CT,16 as in our 2 cases. Retrograde pyelography may be helpful for showing the renal pelvis and cyst communication clearly, and differentiate communicating and noncommunicating cysts.10 We did not use retrograde pyelography for the diagnosis in any patient. Treatment for renal echinococcus is mainly surgical. Total or partial nephrectomy is the treatment of choice. Enucleation, marsupialization and cystectomy have been also described.6, 17 If the preoperative diagnosis involves iso-
lated disease, the retroperitoneal approach should be preferred to avoid disseminating the disease into the peritoneal cavity. The transperitoneal approach can be used in patients with extrarenal involvement. In patients with an unclear preoperative diagnosis radical nephrectomy should be performed. As do others, we also believe that partial nephrectomy causes a risk of dissemination of disease. Thus, total nephrectomy was the preferred treatment in our cases. Intraoperative spillage of the cyst may cause many serious complications, including allergic reactions, anaphylaxia and even death. The kidney should be packed with betadine soaked sponges and the cyst cavity should be filled with scolecidal agents, especially in complicated cases. Preoperative albendazole therapy can be administered in cases suspicious for spillage. As scolecidal agents, 30% sodium chloride, 2% formalin, 1% iodine or 0.5% silver nitrate solutions can be used.8 We prefer to use 2% formalin solution, although it has irritative effects on the surgical team. Hydatid disease is a systemic disorder that affects many organs, such as the liver, lungs, brain and kidney. The anthelmintic agent albendazole can be used in patients with systemic disease but the overall success rate is about 25%.18 Our patients had only isolated renal hydatidosis and they did not have systemic disease. Because none of our patients had received systemic therapy or had recurrence, we believe that surgery alone is the best choice. In the literature some groups describe using anthelmintic therapy with albendazole or mebandazole postoperatively to prevent recurrence,9 but there are inadequate data to support the effectiveness of these drugs. In addition, in such cases it should also be remembered that these drugs have many serious side effects, such as hepatotoxicity, abnormal liver function test results, gastrointestinal symptoms, allergic reactions, leukopenia and alopecia.18 Recently some groups recommended percutaneous management for renal hydatidosis.19, 20 Goel et al performed percutaneous treatment in 4 patients and preserved 3 of 4 renal units.19 They concluded that percutaneous drainage of renal hydatic disease is a safe method associated with a short hospital stay. We believe that this treatment modality carries the risk of dissemination and fatal anaphylactic reactions. We think that further studies in more patients would clarify the usefulness of this technique in renal hydatidosis surgery. CONCLUSIONS
Although isolated renal hydatidosis is uncommon, it should be considered in the differential diagnosis of solid renal masses, especially in suspicious cases. The main treatment is surgery. With appropriate diagnosis and treatment the prognosis is good. REFERENCES
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