Renal angiomyolipoma: evolutional changes of its internal structure on CT

Renal AML Surgically Treated 33 Cases

BACKGROUND: Renal angiomyolipoma (RAML) is a rare benign neoplasm with a prevalence varying between 0.2% and 0.6% and a strong female predilection. They occur as sporadic, isolated entities in 80% of cases. The remaining 20% of angiomyolipomas (AMLs) develop in association with tuberous sclerosis complex or pulmonary lymphangioleiomyomatosis. AIM: We describe our 10-year experience with AML and discuss the treatment strategies employed at our center. METHODS: The medical records of all 33 patients with pathologically confirmed RAML treated either by nephrectomy or nephron-sparing surgery at our center over 10 years were reviewed for patient age and sex, tumor location and size, association with TBS. RESULTS: There were 28 females (84.8%) and 5 males (15.2%) with a median age that was 52 (range 22–74) years at the time of surgery. Thirty patients (90.9%) had sporadic isolated AML, and 3 patients (9.1%) had AML with TBS. The tumor was in the right kidney in 15 (45.5%) patients, in the left kidney in 17 (51.5%) patients, and bilateral in only 1 patient (3%) who was diagnosed with TBS. At presentation, flank pain was the main symptom in 23 patients (69.7%). CONCLUSIONS: Surgical resection of RAML provides short-term symptomatic relieve and long-term survival.

Tuberose sclerosis complex: analysis of growth rates aids differentiation of renal cell carcinoma from atypical or minimal-fat-containing angiomyolipoma

AIM

To study the radiological characteristics of renal masses in individuals with tuberous sclerosis complex (TSC) using serial CT, and to examine how renal cell carcinoma (RCC) may be differentiated from indeterminate cysts or masses.

METHODS

This was a retrospective study of 12 cases of TSC in which dedicated renal CT followed after US had demonstrated cystic or sonographically unusual renal masses. The CT density of all masses was measured and the masses categorized as simple cysts, complex cysts, angiomyolipomas or indeterminate solid masses. Subjects were maintained on regular follow-up with repeat CT or MRI and interval renal US. Indeterminate masses that showed rapid growth were considered suspicious for renal cell carcinoma and biopsy or nephrectomy followed.

RESULTS

Comparative data were available for a median of 4 years. In each case the renal masses were multiple and bilateral; mean mass diameter was 3.6 cm. Among a total of 206 masses, 18 were simple cysts and 3 were complex cysts. Of the complex cysts, 1 proved to be an angiomyolipoma on histology and the other 2 showed no growth. Of the solid masses, 133 were typical angiomyolipomas (AMLs) and 52 were indeterminate. On follow-up, only 3 indeterminate masses showed rapid growth (>0.5 cm/year), of which only 1 proved to be an RCC on biopsy. The other 2 were minimal-fat AMLs, and the remainder of the masses showed no or slow growth.

CONCLUSION

Many renal masses associated with TSC are radiologically indeterminate. A growth threshold of >0.5 cm/year identified the only RCC in this study (0.5% of all masses). Yearly radiological follow-up of indeterminate renal masses is recommended for individuals with TSC.

Nephron-sparing surgery for renal angiomyolipoma

INTRODUCTION

Renal angiomyolipoma (RAML) is a benign tumor composed of varying amounts of mature adipose tissue, smooth muscle and thick-walled blood vessels. RAML tend to grow over time requiring active intervention due to serious associated complications, such as hemorrhage and pain. Although RAML is an ideal tumor for organ preservation, data concerning efficacy of nephron-sparing surgery (NSS) are sparse. The aim of the study was to evaluate the efficacy of NSS in RAML with regard to renal function, tumor recurrence and surgical feasibility.

PATIENTS AND METHODS

Charts of patients with pathologically confirmed RAML were reviewed and data recorded: tumor size, associated symptoms, intraoperative blood loss, serum creatinine, follow-up data with regard to tumor recurrence and long-term renal function. A total of 28 patients were identified with RAML who underwent NSS because of tumor size > 4 cm, pain and/or to rule out malignancy due to radiographic features of uncertain interpretation.

RESULTS

The median follow-up of all patients is 58 (3-114) months; median age was 55.6 (34-78) years, 24 patients were women, 4 patients were men. None of the patients developed a local recurrence. Median size of enucleated tumors was 5.5 (2.5-15) cm; indication for NSS was symptomatic tumor with hemorrhage in 4 patients (16%), prophylaxis of hemorrhage in 5 patients (20%) and radiographic features suspicious for malignancy in 16 patients (64%). In those cases, unenhanced and enhanced CT scans exhibit a hyperdense and a hypodense lesion as compared to the adjacent normal renal cortex, respectively. There were no intraoperative complications, median blood loss was 320 (50-1200) ml, none of the patients required blood transfusions. Post-operative course was uneventful in 26 patients (96%), 2 patients (7.1%) developed a urinary fistula managed by an endoluminal stent. Pre-operative serum creatinine was 0.9 (0.7-1.3) mg/dl, post-operative creatinine was 1.23 (0.7-1.5) mg/dl and serum creatinine at last follow-up was 0.95 (0.7-1.2) mg/dl.

CONCLUSIONS

NSS can be performed with a high success rate in RAML when surgical management is indicated. Long-term follow-up reveals no local tumor recurrences and stable renal function even in patients with a solitary kidney.