Renal angiomyolipoma: its distinctive angiographic characteristics

Sonography in Benign and Malignant Renal Masses

Ultrasonography and CT have allowed improved detection of renal mass lesions. Though ultrasonography is less sensitive in the characterization of the renal mass lesions, it is often the first imaging modality for evacuation of the kidneys. This article gives an overview of the benign and malignant renal mass lesions and the role of ultrasonography in their characterization.

Ethanol and polyvinyl alcohol mixture for transcatheter embolization of renal angiomyolipoma

OBJECTIVE

The purpose of this study was to assess the immediate and midterm effects of embolization of the angiogenic component of renal angiomyolipoma in which a mixture of ethanol and polyvinyl alcohol is used as a permanent obliterator.

MATERIALS AND METHODS

Seventeen patients with 18 renal angiomyolipomas (size range, 5.5-20 cm; mean size, 10 cm) were treated with transcatheter embolization over an 8-year period. Embolization was performed with a mixture of 96% ethanol and polyvinyl alcohol particles. Follow-up with CT (mean follow-up period, 22.4 months) and one (mean, 14 months) or two (mean, 27 months) angiographic examinations were conducted to evaluate changes in the size of the tumor and to look for recurrence of the angiogenic component.

RESULTS

All initial angiograms showed the characteristic tortuous, hypervascular, and aneurysm-forming angiogenic component. Immediate complete obliteration was achieved in 17 tumors (94.4% technical success rate). There was one partial technical failure. Mean tumor size was reduced to 7.6 cm (mean size reduction, 24%). Fourteen patients with 15 tumors underwent one angiographic follow-up examination (mean time after treatment, 14 months), and four patients underwent two angiographic follow-up examinations (mean time after treatment, 27 months). Reduction of the angiogenic component occurred in 10 (66.6%) of the tumors and complete obliteration in five (33.3%) of the tumors. No retroperitoneal hemorrhage or tumor growth was seen during the follow-up period. No complications were encountered.

CONCLUSION

We found a mixture of ethanol and polyvinyl alcohol an efficient embolizing agent with a sustained midterm effect in the management of renal angiomyolipoma. Repeated embolization was needed in tumors with a large angiogenic component. Tumor shrinkage after embolization was minimal.

Angiographic management of retroperitoneal hemorrhage from renal angiomyolipoma in polycystic kidney disease

Angiographic management of bilateral angiomyolipomas complicated by hemorrhage in autosomal dominant polycystic kidney disease is presented. The patient had mild stigmata of tuberous sclerosis, and a family history of tuberous sclerosis and autosomal dominant polycystic kidney disease. The radiographic features at diagnosis, and those present during and after embolization are described. Radiological criteria for diagnosis and successful control of bleeding with intra-arterial selective embolization are discussed. Radiographic features before, during and after embolization are exhibited.

Angiomyolipoma causing life-threatening hematuria in a child with tuberous sclerosis

A case of a 12-year-old boy with tuberous sclerosis who developed life-threatening hematuria is presented. An angiomyolipoma of the lower two thirds of the left kidney resulted in a tumor hemorrhage that was successfully treated by partial nephrectomy.

Renal lesions in tuberous sclerosis

The renal lesion classically associated with tuberous sclerosis is angiomyolipoma. Renal cysts are less frequent, occurring alone or in conjunction with angiomyolipomas. We reviewed the records of 274 patients with tuberous sclerosis registered at our clinic. Of 95 patients evaluated for renal lesions 51 (54 per cent) had positive findings: 45 had angiomyolipomas, 17 had renal cysts and 11 had both lesions. These lesions usually are multiple and bilateral, and are diagnosed most effectively with computerized tomography or ultrasound. Surgery (10 kidneys) was done for life-threatening hemorrhage or suspected malignant lesions.

Renal angiomyolipoma with arteriovenous shunting

We describe a patient with arteriovenous shunting during renal arteriography who at operation was found to have an angiomyolipoma rather than renal cell carcinoma or an arteriovenous malformation. Renal angiomyolipoma should be added to the list of causes of gross hematuria with angiographically demonstrable arteriovenous shunting.

Renal tumors associated with tuberous sclerosis: the case for aggressive surgical management

Tuberous sclerosis is associated commonly with renal angiomyolipoma. However, the radiographic differentiation of angiomyolipoma and renal carcinoma can be difficult, and the natural history of angiomyolipoma may be associated with serious complications. We present a case of bilateral renal cell carcinoma associated with tuberous sclerosis. Aggressive but conserving renal surgery should be considered in patients with tuberous sclerosis and enlarging renal masses.

Ultrasonography, computerized transaxial tomography and pathology of angiomyolipoma of the kidney: solution to a diagnostic dilemma

The review of 9 anatomically proved cases of angiomyolipomas of the kidney has revealed characteristic findings of marked echoes on ultrasonography and areas of fat attenuation on computerized transaxial tomography. These 2 findings should resolve the diagnostic dilemma in this benign lesion and prevent the need for operation intervention in most cases.

Parasitic arterial supply to renal angiomyolipoma

A case of a large renal angiomyolipoma in a relatively asymptomatic female subject without tuberous sclerosis is presented. The case demonstrates a parasitized blood supply from a lumbar artery and the superior mesenteric artery, in addition to the characteristic angiographic features that have been reported previously. A parasitized blood supply to renal masses has been considered previously to be associated with malignant processes. It is emphasized that parasitization of a blood supply by a renal mass lesion is not definite evidence of malignancy.

Preoperative diagnosis of renal angiomyolipoma

Six cases of renal angiomyolipoma are reviewed. In 5 of these 6 cases a characteristics radiolucent fat sign was present overlying the renal mass. In 10 cases of hypernephroma selected only on the basis of a tissue diagnosis and the availability of a pre-injection scout film this sign was not present. The recent literature is reviewed on the radiographic diagnosis of angiomyolipoma. We conclude that angiography is not reliable in the differentiation of angiomyolipoma from hypernephroma. However, demonstration of a radiolucency on the pre-injection scout film is virtually pathognomonic of angiomyolipoma. Tomographic cuts without contrast injection may increase diagnostic accuracy.

Angiographic manifestations of renal hamartoma

Two types of renal hamartoma (angiomyolipoma) are presented with emphasis on angiographic findings. Careful analysis of the angiograms can suggest a specific diagnosis. Two important considerations other than angiographic findings are (1) multiplicity of tumors in patients with tuberous sclerosis, and (2) a solitary mass in 40-60-year-old women.

Renal sinus angiomyolipoma

The first case of an angiomyolipoma limited to the renal sinus is presented. The radiographic findings were a relatively lucent mass within the renal sinus (extrarenal); neovascularity that did not respond to epinephrine; lack of arteriovenous shunting; a "whorled" venous pattern; and displacement and compression of the renal vein without evidence of invasion. Infusion nephrotomography and renal venography were crucial in the localization and preoperative suggestion of this benign renal sinus lesion. The renal sinus angiomyolipoma was removed by blunt dissection and the kidney preserved.

Parasitic lumbar arterial blood supply in renal angiomyolipoma

A young woman with azotemia was found to have an angiomyolipoma which had parasitic blood supply from a lumbar artery. Parasitic lumbar arterial blood supply from a lumbar artery. Parasitic lumbar arterial blood supply has previously been considered a strong indication of malignancy. Since this benign lesion had not invaded the adjacent retroperitoneal structures, the phenomenon tends to confirm the postulate that parasitic blood supply to a lesion may occur through hypertrophy of small anastomotic channels normally present between adjacent vessels but not normally seen in angiography.

The angiographic appearance of renal angiomyolipoma and problems of its preoperative diagnosis

The radiodiagnostic difficulties of renal hamartoma (renal angiomyolipoma) have been discussed in connection with the authors' two cases. In the first case a unifocal cystic renal angiomyolipoma without tuberous sclerosis caused retroperitoneal haematoma and acute symptoms. In the second case a preoperative tentative diagnosis of angiomyolipoma was made, however, the Pringle-type dermal lesions were only observed 6 months after surgery on control examination. The authors state that the radiographic functional findings vary depending on the tissue structure of the tumour. Differential diagnosis of cystic angiomyolipoma containing little fatty and angiomatous tissue is impossible, whereas for the hypervascular variant a tentative diagnosis can be established even in the case of unifocal hamartoma.

Angiomyolipoma and renal cell carcinoma in same kidney

A case of renal cell carcinoma and angiomyolipoma occurring in the same kidney in a patient without stigmata of tuberous sclerosis is reported. This case was managed as malignant renal tumor, and the patient underwent radical nephrectomy. Urologic and angiographic literature regarding angiomyolipoma is reviewed, and we find the neovascularity of this benign tumor is only rarely distinguishable from malignant renal tumor.