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Benign Renal Angiomyolipoma With Inferior Vena Cava Thrombosis
Surgeon’s Workshop Benign Renal Angiomyolipoma With Inferior Vena Cava Thrombosis Varun Mittal, Baldev S. Aulakh, and Garima Daga OBJECTIVE
METHODS RESULTS
CONCLUSION
To present a new case of an uncommon complication of a benign renal tumor. To our knowledge, there are only few published cases of benign renal angiomyolipoma (AML) presenting with tumor thrombus in females. Epithelioid angiomyolipoma is a recently described rare variant of renal angiomyolipoma. It can occur in patients with or without tuberous sclerosis, and may potentially be malignant. Benign renal angiomyolipoma AML rarely presents with evidence of extension into the renal vein, inferior vena cava (IVC) or atrium. We report a case of a benign renal AML with a tumor thrombus to the IVC in a 46-year-old female who presented with right-sided flank pain associated with a right sided abdominal mass. Right Radical nephrectomy with IVC tumor thrombectomy. Patient is totally asymptomatic. At 1 month after surgery, an abdominal ultrasound showed no evidence of thrombus within the IVC. CT scan of the abdomen at 3 months post-operatively showed no evidence of recurrence. Surgical treatment of angiomyolipoma with IVC thrombus is warranted in view of risk of malignancy and to prevent tumor embolus to the heart or lungs. UROLOGY 77: 1503–1506, 2011. © 2011 Elsevier Inc.
R
enal angiomyolipoma (AML) is typically a solid lesion, composed of dystrophic vessels, smooth muscle cells, and adipose tissue lacking an epithelial component. It has an incidence of about 0.3%3%. Two types have been described: isolated AML (80%) and AML associated with tuberous sclerosis (20%). Isolated AML occurs sporadically and are often solitary. The mean age at presentation is 43 years, with a female preponderance (male/female ratio of 4:11). Finally, 80% of the cases have involved the right kidney. AMLs in association with tuberous sclerosis have typically been larger than isolated AMLs and are often bilateral and multiple. AMLs occur in 80% of patients with tuberous sclerosis. The male/female distribution in patients with tuberous sclerosis has been nearly equal, but the prevalence has been greater in women. Most lesions are small and asymptomatic and have been found incidentally on imaging studies. As many as 40% of patients will be symptomatic, with a palpable abdominal mass that can result in hematuria or flank pain. Solitary sporadic tumors can cause an acute abdomen and shock because of spontaneous hemorrhage in the tumor (Wun-
From the Department of Urology and Transplant, Dayanand Medical College, Ludhiana, Punjab, India; and Department of Surgery, Dayanand Medical College and Hospital, Ludhiana, Punjab, India Reprint requests: Varun Mittal, M.B.B.S., M.S., Department of Urology and Transplant, Dayanand Medical College, Ludhiana, Punjab 141001 India. E-mail: [email protected] Submitted: January 11, 2011, accepted (with revisions): January 18, 2011
© 2011 Elsevier Inc. All Rights Reserved
derlich syndrome). The demonstration of fatty attenuation in the renal tumor on computed tomography (CT) is virtually diagnostic of AML. Although AMLs are considered benign, rare cases possibly related to multicentric disease have been reported with extension into the renal vein or inferior vena cava (IVC), or both. Also, deposits in the regional lymph nodes have been reported, in particular, with tumor demonstrating the presence of epithelioid cells. A risk exists of tumor embolus to the heart or lungs. Surgical treatment is therefore warranted in view of the risk of malignancy and to prevent the risk of tumor embolus to the heart or lungs.
CASE REPORT A 46-year-old woman with no stigmata of tuberous sclerosis was referred with a 4-6-month period of right flank pain. The physical examination revealed a right renal mass, and the laboratory tests results were unremarkable. Magnetic resonance imaging of the abdomen showed a high-intensity tumor (suggested of some fatty elements) in the right kidney and a tumor thrombus in the main renal vein and IVC (Fig. 1). The possibility of AML, replacement lipomatosis, and atypical renal cell carcinoma were considered. Thus, the patient underwent right radical nephrectomy and IVC thrombectomy. We used a midline transperitoneal approach and fully mobilized the right kidney. The tumor thrombus was identified in the 0090-4295/11/$36.00 doi:10.1016/j.urology.2011.01.039
1503
Figure 1. Magnetic resonance images showing right renal upper pole tumor with fatty elements with tumor thrombus extending into IVC.
COMMENT
Figure 2. Intraoperative picture showing tumor thrombus floating in IVC.
main right renal vein and IVC (Fig. 2). Next, using Satinsky clamps, vascular control of the IVC and left renal vein was achieved, and, by way of an anterior cavotomy, the tumor thrombus was delivered intact and the cavotomy was repaired (Fig. 3). With the tumor thrombus removed, right radical nephrectomy was safely performed. No enlarged lymph nodes were found, and the tumor thrombus did not adhere to the IVC wall. Macroscopic examination showed a 7 ⫻ 7 ⫻ 4.5-cm tumor in the right kidney extending into the perirenal fat and tumor thrombus in the right main renal vein and IVC (Fig. 3). Microscopic examination showed mature fatty tissue, a few vessels, and irregular bundles of the smooth muscle cells around the blood vessels in a radial fashion; most were epithelioid cells. No cytologic atypia, mitosis, or necrosis was seen in the sections examined. Adjacent renal parenchyma and the adrenal gland showed no specific abnormalities. At 1 month postoperatively, abdominal ultrasonography showed no evidence of thrombus within the IVC. CT of the abdomen at 3 months postoperatively showed no evidence of recurrence. 1504
Renal AML is typically a solid lesion, composed of adipose tissue, dystrophic vessels, and smooth muscle cells, lacking an epithelial component.1 The extrarenal sites for AML include the liver, spleen, abdominal wall, retroperitoneum, uterus, oral cavity, penis, spermatic cord, fallopian tube, vagina, skin, and lung.2 About 80% of renal AMLs occur sporadically, and 20% occur in patients with tuberous sclerosis complex (TSC).3 AMLs can also occur in association with other phacomatoses (eg, von Recklinghausen disease, von Hippel-Lindau disease, Sturge-Weber syndrome), autosomal dominant polycystic disease, and pulmonary lymphangiomyomatosis.2,3 This unusual benign tumor accounts for 3% of all solid kidney tumors, with a female predominance (male/female ratio 4:11). AMLs are seen rarely in children without associated TSC.3 The conventional AML usually follows a benign course of slow growth and local development. Accelerated growth can be observed in larger masses, multiple tumors, and during pregnancy. Mostly, 77% of tumors will be ⬍4 cm and are asymptomatic; 82% of AMLs ⬎4 cm produce symptoms. The presenting symptoms primarily include fever, nausea, vomiting, pain, palpable mass, hematuria, hypertension, anemia, renal failure, and shock. Retroperitoneal hemorrhage (Wunderlich syndrome) occurs in ⱕ50% of patients with tumors ⬎4 cm, in those with TSC, and in those with numerous confluent AMLs. Urinary tract infection is an uncommon presentation. AMLs can coexist with malignant lesions, such as sarcoma and renal cell carcinoma.4 Only a few reports have been published of the transformation of classic AML to malignant sarcomatoid epithelioid AML.4 The extension of a renal AML into the renal vein, IVC, or atrium is a significant point of morbidity with this disease.5 Only a few case reports of AML with tumor extension have been published. Most of these cases have been seen in women. In a review of ⬎20 classic AMLs UROLOGY 77 (6), 2011
Figure 3. After vascular control with Satinsky clamps, cavotomy was performed and tumor thrombus popped out and removed intact with radical nephrectomy specimen and cavotomy closed. Specimen from right radical nephrectomy shown with thrombus in renal vein.
with extension into the vena cava and 40 with regional lymph node involvement, Eble6 found that all were benign, and none had additional progression after resection. However, it would be incorrect to say that the diagnosis of renal AML is unequivocally established whenever adipose tissue has been demonstrated on CT, because lipoma, liposarcoma, teratoma, Wilms tumor, oncocytoma, and renal cell carcinoma can contain fat and can be difficult to differentiate on imaging studies.7 As reported by Helenon et al,7 xanthogranulomatous pyelonephritis, ephrogenic rests, and perinephric abscesses can also mimic AMLs. Lemaitre et al8 studied the ultrasound and CT features of AMLs in 60 cases. The classic findings of a wellcircumscribed and highly echogenic lesion on ultrasonography were observed in only 60%. Renal cell carcinoma mimicked AMLs in 47% of cases by appearing markedly hyperechoic on ultrasonography owing to cystic degeneration, necrosis, and other changes. The diagnosis can be made using CT; adipose tissue areas with negative density (⫺20 to ⫺100 Hounsfield units) in the lesion have been considered the hallmark of AML.9 However, 5% of AMLs will not have any fatty tissue visible on CT. The epithelioid form of AML is a singular entity, with a poor prognosis, which contains no adipose tissue and can be mistaken for renal cell carcinoma. Calcification is rarely seen in AMLs and more often indicates renal cell carcinoma. Magnetic resonance imaging does not appear to provide any advantages compared with CT, except when intravenous contrast administration is contraindicated.10 Fine needle biopsy can be used in equivocal cases. Biopsy UROLOGY 77 (6), 2011
is subject to sampling error, the interpretation of pleomorphic cells is difficult, and the occurrence of severe hemorrhage is a risk. The best treatment of patients with AML is a matter of controversy. Oesterling et al11 reviewed 602 cases of AML and found that the tumor size and the symptoms it produced were the most important factors in selecting a management option. They recommended that asymptomatic patients be evaluated with ultrasonography or CT every 6 months (tumors ⱖ4 cm) to 1 year (tumors ⬍4 cm), depending on the tumor size. Symptomatic patients were observed only if symptoms resolved promptly and the tumors were ⬍4 cm. Otherwise, angiographic embolization and/or nephron-sparing surgery was suggested for all symptomatic tumors. This management scheme was applicable to all AMLs, including those in patients with associated TSC. In contrast, Steiner et al12 reported that in TSC, AMLs were more likely to grow and recommended semiannual tumor imaging in these patients. Prophylactic angiographic embolization and/or nephron-sparing surgery should be considered for patients with asymptomatic tumors that were ⱖ4 cm and associated with TSC and asymptomatic lesions ⬍4 cm when significant growth was seen. Dickinson et al13 found that AMLs 4-8 cm in size were the most unpredictable and recommended treatment of patients who were at risk of trauma or had lesions with significant growth or symptoms and tumors ⬎8 cm. Delworth et al14 experimentally treated a patient with a 10-cm AML in a solitary kidney using cryotherapy through an open flank incision; 10% enlargement of the 1505
AML was observed on the CT scan 3 months later. Embolosation is effective in controlling active bleeding and for management of symptomatic AMLs ⬎4 cm. Fazeli-Matin and Novick15 demonstrated the longterm efficacy (no postoperative recurrences, symptoms, or dialysis) of nephron-sparing surgery in 27 patients during 17 years and cited the major pitfalls of selective angioembolization in the published data (continued symptoms, postembolization syndrome, repeated embolizations, catheter drainage necrosis, complications leading to loss of renal function, and subsequent nephrectomy). Yip et al16 emphasized that nephron-sparing surgery was most useful when a histologic diagnosis was in doubt. In the present case, the patient chose to undergo partial nephrectomy. AMLs invading the renal vein or IVC carry the risk of potentially fatal cardiopulmonary embolism and death. Surgical treatment (eg, radical nephrectomy plus tumor thrombectomy) of these lesions is indicated even when they are asymptomatic.15-19 For the most patients with supradiaphragmatic or right atrial tumor thrombi, the preferred approach is to use cardiopulmonary bypass with deep hypothermic circulatory arrest.20 A comprehensive approach with transesophageal echocardiographic monitoring for cardiac embolus and collaboration between vascular and urologic surgeons should be considered in cases of extension of tumor thrombus to right atria.21 In our patient, we performed right radical nephrectomy with IVC tumor thrombectomy.
CONCLUSIONS Renal AML is an uncommon benign tumor with a female predominance. Malignant transformation of classic AML to sarcomatoid epithelioid AML is rare but known; thus, the presence of epitheloid cells should not be overlooked. Only a few cases with tumor thrombus in the IVC or renal vein have been reported. The present case has shown that urologists should consider the rare possibility that renal AML can invade the renal vein or IVC. Also, because of the risk of potentially fatal cardiopulmonary embolism and death, surgical treatment (radical nephrectomy plus tumor thrombectomy) of these lesions is indicated even when asymptomatic. References 1. Nelson CP, Sanda MG. Contemporary diagnosis and management of renal angiomyolipoma. J Urol. 2002;168:1315-1325.
1506
2. Logginidou H, Ao X, Russo I, et al. Frequent estrogen and progesterone receptor immunoreactivity in renal angiomyolipomas from women with pulmonary lymphangioleiomyomatosis. Chest. 2000; 117:25-30. 3. Rakowski SK, Winterkorn EB, Paul E, et al. Renal manifestations of tuberous sclerosis complex: incidence, prognosis, and predictive factors. Kidney Int. 2006;70:1777-1782. 4. Cibas ES, Goss GA, Kulke MH, et al. Malignant epithelioid angiomyolipoma (“sarcoma ex angiomyolipoma”) of the kidney: a case report and review of the literature. Am J Surg Pathol. 2001;25: 121-126. 5. Wilson SS, Clark PE, Stein JP. Angiomyolipoma with vena caval extension. Urology. 2002;60:695-696. 6. Eble JN. Angiomyolipoma of kidney. Semin Diagn Pathol. 1998;15: 21-40. 7. Helenon O, Merran S, Paraf F, et al. Unusual fat-containing tumors of the kidney: a diagnostic dilemma. RadioGraphics. 1997;17:129144. 8. Lemaitre L, Claudon M, Dubrulle F, et al. Imaging of angiomyolipomas. Semin Ultrasound CT MR. 1997;18:100-114. 9. Friedman AC, Hartman DS, Sherman J, et al. Computed tomography of abdominal fatty masses. Radiology. 1981;139:415-429. 10. Israel GM, Hindman N, Hecht E, et al. The use of opposed-phase chemical shift MRI in the diagnosis of renal angiomyolipomas. AJR Am J Roentgenol. 2005;184:1868-1872. 11. Oesterling JE, Fishman EK, Goldman SM, et al. The management of renal angiomyolipoma. Urology. 1986;135:1121-1124. 12. Steiner MS, Goldman SM, Fishman EK, et al. The natural history of renal angiomyolipoma. J Urol. 1993;150:1782-1786. 13. Dickinson M, Ruckle H, Beaghler M, et al. Renal angiomyolipoma: optimal treatment based on size and symptoms. Clin Nephrol. 1998; 49:281-286. 14. Delworth MG, Pisters LL, Fornage BD, et al. Cryotherapy for renal cell carcinoma and angiomyolipoma. J Urol. 1996;155:252-255. 15. Fazeli-Matin S, Novick AC. Nephron-sparing surgery for renal angiomyolipoma. Urology. 1998;52:577-583. 16. Yip SK, Tan PH, Cheng WS, et al. Surgical management of angiomyolipoma: nephron-sparing surgery for symptomatic tumour. Scand J Urol Nephrol. 2000;34:32-35. 17. Kothary N, Soulen MC, Clark TWI, et al. Renal angiomyolipoma: long-term results after arterial embolization. J Vasc Interv Radiol. 2005;16:45-50. 18. Haritharan T, Sritharan S, Bhimji S. Renal angiomyolipoma with inferior vena caval involvement. Med J Malays. 2006;61:493-495. 19. Gamé X, Soulié M, Moussouni S, et al. Renal angiomyolipoma associated with rapid enlargement and inferior vena caval tumor thrombus. J Urol. 2003;170:918-919. 20. Novick AC, Kaye M, Cosgrove D, et al. Experience with cardiopulmonary bypass and deep hypothermic circulatory arrest in the management of retroperitoneal tumors with large vena caval thrombi. Ann Surg. 1990;212:472-477. 21. Ito H, Nakashima S, Toma H, et al. Renal angiomyolipoma associated with inferior vena caval and right atrial thrombus. J Urol. 1999;162:1371-1372.
UROLOGY 77 (6), 2011
METHODS RESULTS
CONCLUSION
To present a new case of an uncommon complication of a benign renal tumor. To our knowledge, there are only few published cases of benign renal angiomyolipoma (AML) presenting with tumor thrombus in females. Epithelioid angiomyolipoma is a recently described rare variant of renal angiomyolipoma. It can occur in patients with or without tuberous sclerosis, and may potentially be malignant. Benign renal angiomyolipoma AML rarely presents with evidence of extension into the renal vein, inferior vena cava (IVC) or atrium. We report a case of a benign renal AML with a tumor thrombus to the IVC in a 46-year-old female who presented with right-sided flank pain associated with a right sided abdominal mass. Right Radical nephrectomy with IVC tumor thrombectomy. Patient is totally asymptomatic. At 1 month after surgery, an abdominal ultrasound showed no evidence of thrombus within the IVC. CT scan of the abdomen at 3 months post-operatively showed no evidence of recurrence. Surgical treatment of angiomyolipoma with IVC thrombus is warranted in view of risk of malignancy and to prevent tumor embolus to the heart or lungs. UROLOGY 77: 1503–1506, 2011. © 2011 Elsevier Inc.
R
enal angiomyolipoma (AML) is typically a solid lesion, composed of dystrophic vessels, smooth muscle cells, and adipose tissue lacking an epithelial component. It has an incidence of about 0.3%3%. Two types have been described: isolated AML (80%) and AML associated with tuberous sclerosis (20%). Isolated AML occurs sporadically and are often solitary. The mean age at presentation is 43 years, with a female preponderance (male/female ratio of 4:11). Finally, 80% of the cases have involved the right kidney. AMLs in association with tuberous sclerosis have typically been larger than isolated AMLs and are often bilateral and multiple. AMLs occur in 80% of patients with tuberous sclerosis. The male/female distribution in patients with tuberous sclerosis has been nearly equal, but the prevalence has been greater in women. Most lesions are small and asymptomatic and have been found incidentally on imaging studies. As many as 40% of patients will be symptomatic, with a palpable abdominal mass that can result in hematuria or flank pain. Solitary sporadic tumors can cause an acute abdomen and shock because of spontaneous hemorrhage in the tumor (Wun-
From the Department of Urology and Transplant, Dayanand Medical College, Ludhiana, Punjab, India; and Department of Surgery, Dayanand Medical College and Hospital, Ludhiana, Punjab, India Reprint requests: Varun Mittal, M.B.B.S., M.S., Department of Urology and Transplant, Dayanand Medical College, Ludhiana, Punjab 141001 India. E-mail: [email protected] Submitted: January 11, 2011, accepted (with revisions): January 18, 2011
© 2011 Elsevier Inc. All Rights Reserved
derlich syndrome). The demonstration of fatty attenuation in the renal tumor on computed tomography (CT) is virtually diagnostic of AML. Although AMLs are considered benign, rare cases possibly related to multicentric disease have been reported with extension into the renal vein or inferior vena cava (IVC), or both. Also, deposits in the regional lymph nodes have been reported, in particular, with tumor demonstrating the presence of epithelioid cells. A risk exists of tumor embolus to the heart or lungs. Surgical treatment is therefore warranted in view of the risk of malignancy and to prevent the risk of tumor embolus to the heart or lungs.
CASE REPORT A 46-year-old woman with no stigmata of tuberous sclerosis was referred with a 4-6-month period of right flank pain. The physical examination revealed a right renal mass, and the laboratory tests results were unremarkable. Magnetic resonance imaging of the abdomen showed a high-intensity tumor (suggested of some fatty elements) in the right kidney and a tumor thrombus in the main renal vein and IVC (Fig. 1). The possibility of AML, replacement lipomatosis, and atypical renal cell carcinoma were considered. Thus, the patient underwent right radical nephrectomy and IVC thrombectomy. We used a midline transperitoneal approach and fully mobilized the right kidney. The tumor thrombus was identified in the 0090-4295/11/$36.00 doi:10.1016/j.urology.2011.01.039
1503
Figure 1. Magnetic resonance images showing right renal upper pole tumor with fatty elements with tumor thrombus extending into IVC.
COMMENT
Figure 2. Intraoperative picture showing tumor thrombus floating in IVC.
main right renal vein and IVC (Fig. 2). Next, using Satinsky clamps, vascular control of the IVC and left renal vein was achieved, and, by way of an anterior cavotomy, the tumor thrombus was delivered intact and the cavotomy was repaired (Fig. 3). With the tumor thrombus removed, right radical nephrectomy was safely performed. No enlarged lymph nodes were found, and the tumor thrombus did not adhere to the IVC wall. Macroscopic examination showed a 7 ⫻ 7 ⫻ 4.5-cm tumor in the right kidney extending into the perirenal fat and tumor thrombus in the right main renal vein and IVC (Fig. 3). Microscopic examination showed mature fatty tissue, a few vessels, and irregular bundles of the smooth muscle cells around the blood vessels in a radial fashion; most were epithelioid cells. No cytologic atypia, mitosis, or necrosis was seen in the sections examined. Adjacent renal parenchyma and the adrenal gland showed no specific abnormalities. At 1 month postoperatively, abdominal ultrasonography showed no evidence of thrombus within the IVC. CT of the abdomen at 3 months postoperatively showed no evidence of recurrence. 1504
Renal AML is typically a solid lesion, composed of adipose tissue, dystrophic vessels, and smooth muscle cells, lacking an epithelial component.1 The extrarenal sites for AML include the liver, spleen, abdominal wall, retroperitoneum, uterus, oral cavity, penis, spermatic cord, fallopian tube, vagina, skin, and lung.2 About 80% of renal AMLs occur sporadically, and 20% occur in patients with tuberous sclerosis complex (TSC).3 AMLs can also occur in association with other phacomatoses (eg, von Recklinghausen disease, von Hippel-Lindau disease, Sturge-Weber syndrome), autosomal dominant polycystic disease, and pulmonary lymphangiomyomatosis.2,3 This unusual benign tumor accounts for 3% of all solid kidney tumors, with a female predominance (male/female ratio 4:11). AMLs are seen rarely in children without associated TSC.3 The conventional AML usually follows a benign course of slow growth and local development. Accelerated growth can be observed in larger masses, multiple tumors, and during pregnancy. Mostly, 77% of tumors will be ⬍4 cm and are asymptomatic; 82% of AMLs ⬎4 cm produce symptoms. The presenting symptoms primarily include fever, nausea, vomiting, pain, palpable mass, hematuria, hypertension, anemia, renal failure, and shock. Retroperitoneal hemorrhage (Wunderlich syndrome) occurs in ⱕ50% of patients with tumors ⬎4 cm, in those with TSC, and in those with numerous confluent AMLs. Urinary tract infection is an uncommon presentation. AMLs can coexist with malignant lesions, such as sarcoma and renal cell carcinoma.4 Only a few reports have been published of the transformation of classic AML to malignant sarcomatoid epithelioid AML.4 The extension of a renal AML into the renal vein, IVC, or atrium is a significant point of morbidity with this disease.5 Only a few case reports of AML with tumor extension have been published. Most of these cases have been seen in women. In a review of ⬎20 classic AMLs UROLOGY 77 (6), 2011
Figure 3. After vascular control with Satinsky clamps, cavotomy was performed and tumor thrombus popped out and removed intact with radical nephrectomy specimen and cavotomy closed. Specimen from right radical nephrectomy shown with thrombus in renal vein.
with extension into the vena cava and 40 with regional lymph node involvement, Eble6 found that all were benign, and none had additional progression after resection. However, it would be incorrect to say that the diagnosis of renal AML is unequivocally established whenever adipose tissue has been demonstrated on CT, because lipoma, liposarcoma, teratoma, Wilms tumor, oncocytoma, and renal cell carcinoma can contain fat and can be difficult to differentiate on imaging studies.7 As reported by Helenon et al,7 xanthogranulomatous pyelonephritis, ephrogenic rests, and perinephric abscesses can also mimic AMLs. Lemaitre et al8 studied the ultrasound and CT features of AMLs in 60 cases. The classic findings of a wellcircumscribed and highly echogenic lesion on ultrasonography were observed in only 60%. Renal cell carcinoma mimicked AMLs in 47% of cases by appearing markedly hyperechoic on ultrasonography owing to cystic degeneration, necrosis, and other changes. The diagnosis can be made using CT; adipose tissue areas with negative density (⫺20 to ⫺100 Hounsfield units) in the lesion have been considered the hallmark of AML.9 However, 5% of AMLs will not have any fatty tissue visible on CT. The epithelioid form of AML is a singular entity, with a poor prognosis, which contains no adipose tissue and can be mistaken for renal cell carcinoma. Calcification is rarely seen in AMLs and more often indicates renal cell carcinoma. Magnetic resonance imaging does not appear to provide any advantages compared with CT, except when intravenous contrast administration is contraindicated.10 Fine needle biopsy can be used in equivocal cases. Biopsy UROLOGY 77 (6), 2011
is subject to sampling error, the interpretation of pleomorphic cells is difficult, and the occurrence of severe hemorrhage is a risk. The best treatment of patients with AML is a matter of controversy. Oesterling et al11 reviewed 602 cases of AML and found that the tumor size and the symptoms it produced were the most important factors in selecting a management option. They recommended that asymptomatic patients be evaluated with ultrasonography or CT every 6 months (tumors ⱖ4 cm) to 1 year (tumors ⬍4 cm), depending on the tumor size. Symptomatic patients were observed only if symptoms resolved promptly and the tumors were ⬍4 cm. Otherwise, angiographic embolization and/or nephron-sparing surgery was suggested for all symptomatic tumors. This management scheme was applicable to all AMLs, including those in patients with associated TSC. In contrast, Steiner et al12 reported that in TSC, AMLs were more likely to grow and recommended semiannual tumor imaging in these patients. Prophylactic angiographic embolization and/or nephron-sparing surgery should be considered for patients with asymptomatic tumors that were ⱖ4 cm and associated with TSC and asymptomatic lesions ⬍4 cm when significant growth was seen. Dickinson et al13 found that AMLs 4-8 cm in size were the most unpredictable and recommended treatment of patients who were at risk of trauma or had lesions with significant growth or symptoms and tumors ⬎8 cm. Delworth et al14 experimentally treated a patient with a 10-cm AML in a solitary kidney using cryotherapy through an open flank incision; 10% enlargement of the 1505
AML was observed on the CT scan 3 months later. Embolosation is effective in controlling active bleeding and for management of symptomatic AMLs ⬎4 cm. Fazeli-Matin and Novick15 demonstrated the longterm efficacy (no postoperative recurrences, symptoms, or dialysis) of nephron-sparing surgery in 27 patients during 17 years and cited the major pitfalls of selective angioembolization in the published data (continued symptoms, postembolization syndrome, repeated embolizations, catheter drainage necrosis, complications leading to loss of renal function, and subsequent nephrectomy). Yip et al16 emphasized that nephron-sparing surgery was most useful when a histologic diagnosis was in doubt. In the present case, the patient chose to undergo partial nephrectomy. AMLs invading the renal vein or IVC carry the risk of potentially fatal cardiopulmonary embolism and death. Surgical treatment (eg, radical nephrectomy plus tumor thrombectomy) of these lesions is indicated even when they are asymptomatic.15-19 For the most patients with supradiaphragmatic or right atrial tumor thrombi, the preferred approach is to use cardiopulmonary bypass with deep hypothermic circulatory arrest.20 A comprehensive approach with transesophageal echocardiographic monitoring for cardiac embolus and collaboration between vascular and urologic surgeons should be considered in cases of extension of tumor thrombus to right atria.21 In our patient, we performed right radical nephrectomy with IVC tumor thrombectomy.
CONCLUSIONS Renal AML is an uncommon benign tumor with a female predominance. Malignant transformation of classic AML to sarcomatoid epithelioid AML is rare but known; thus, the presence of epitheloid cells should not be overlooked. Only a few cases with tumor thrombus in the IVC or renal vein have been reported. The present case has shown that urologists should consider the rare possibility that renal AML can invade the renal vein or IVC. Also, because of the risk of potentially fatal cardiopulmonary embolism and death, surgical treatment (radical nephrectomy plus tumor thrombectomy) of these lesions is indicated even when asymptomatic. References 1. Nelson CP, Sanda MG. Contemporary diagnosis and management of renal angiomyolipoma. J Urol. 2002;168:1315-1325.
1506
2. Logginidou H, Ao X, Russo I, et al. Frequent estrogen and progesterone receptor immunoreactivity in renal angiomyolipomas from women with pulmonary lymphangioleiomyomatosis. Chest. 2000; 117:25-30. 3. Rakowski SK, Winterkorn EB, Paul E, et al. Renal manifestations of tuberous sclerosis complex: incidence, prognosis, and predictive factors. Kidney Int. 2006;70:1777-1782. 4. Cibas ES, Goss GA, Kulke MH, et al. Malignant epithelioid angiomyolipoma (“sarcoma ex angiomyolipoma”) of the kidney: a case report and review of the literature. Am J Surg Pathol. 2001;25: 121-126. 5. Wilson SS, Clark PE, Stein JP. Angiomyolipoma with vena caval extension. Urology. 2002;60:695-696. 6. Eble JN. Angiomyolipoma of kidney. Semin Diagn Pathol. 1998;15: 21-40. 7. Helenon O, Merran S, Paraf F, et al. Unusual fat-containing tumors of the kidney: a diagnostic dilemma. RadioGraphics. 1997;17:129144. 8. Lemaitre L, Claudon M, Dubrulle F, et al. Imaging of angiomyolipomas. Semin Ultrasound CT MR. 1997;18:100-114. 9. Friedman AC, Hartman DS, Sherman J, et al. Computed tomography of abdominal fatty masses. Radiology. 1981;139:415-429. 10. Israel GM, Hindman N, Hecht E, et al. The use of opposed-phase chemical shift MRI in the diagnosis of renal angiomyolipomas. AJR Am J Roentgenol. 2005;184:1868-1872. 11. Oesterling JE, Fishman EK, Goldman SM, et al. The management of renal angiomyolipoma. Urology. 1986;135:1121-1124. 12. Steiner MS, Goldman SM, Fishman EK, et al. The natural history of renal angiomyolipoma. J Urol. 1993;150:1782-1786. 13. Dickinson M, Ruckle H, Beaghler M, et al. Renal angiomyolipoma: optimal treatment based on size and symptoms. Clin Nephrol. 1998; 49:281-286. 14. Delworth MG, Pisters LL, Fornage BD, et al. Cryotherapy for renal cell carcinoma and angiomyolipoma. J Urol. 1996;155:252-255. 15. Fazeli-Matin S, Novick AC. Nephron-sparing surgery for renal angiomyolipoma. Urology. 1998;52:577-583. 16. Yip SK, Tan PH, Cheng WS, et al. Surgical management of angiomyolipoma: nephron-sparing surgery for symptomatic tumour. Scand J Urol Nephrol. 2000;34:32-35. 17. Kothary N, Soulen MC, Clark TWI, et al. Renal angiomyolipoma: long-term results after arterial embolization. J Vasc Interv Radiol. 2005;16:45-50. 18. Haritharan T, Sritharan S, Bhimji S. Renal angiomyolipoma with inferior vena caval involvement. Med J Malays. 2006;61:493-495. 19. Gamé X, Soulié M, Moussouni S, et al. Renal angiomyolipoma associated with rapid enlargement and inferior vena caval tumor thrombus. J Urol. 2003;170:918-919. 20. Novick AC, Kaye M, Cosgrove D, et al. Experience with cardiopulmonary bypass and deep hypothermic circulatory arrest in the management of retroperitoneal tumors with large vena caval thrombi. Ann Surg. 1990;212:472-477. 21. Ito H, Nakashima S, Toma H, et al. Renal angiomyolipoma associated with inferior vena caval and right atrial thrombus. J Urol. 1999;162:1371-1372.
UROLOGY 77 (6), 2011