Images

Doctor's Information

Name : Morteza
Family : Sanei Taheri
Affiliation :Radiology Department,Shohada Tajrish Hospital,SBMU
Academic Degree : Associate Professor of Radiology
Email : This email address is being protected from spambots. You need JavaScript enabled to view it.
Resident : Maryam Sheikh

Case Section

Abdominal Imaging

Patient's Information

Gender : Female
Age : 50

Clinical Summary

50y/o woman with sudden onset Right flank pain

Imaging Findings

The CT images show a fat containing mass with approximate diameter of 80×50 mm and internal hyperdense areas in Rt kidney,surrounding fat stranding in posterior pararenal area is seen .

Differential Diagnosis

RCC with invasion of perinephric fat and hemorrhage RCC with metaplasia and hemorrhage

Final Diagnosis

Hemorrhagic angiomyolipoma( AML)

Discussion (Related Text)

Angiomyolipoma(AML) is a benign renal neoplasm composed of fat,vascular and smooth muscle elements80% of cases of AML,have the sporadic type of AML which is isolated.The mean age at presentation of the isolated AML,is 43 y/o .This kind of AML is 4 times more common in women than in men.Interestingly,80% of the cases involve the Rt kidney. The other 20% of cases of AML have AML associated with TS.The lesions are typically larger than isolated AML,and they are bilateral and multiple.AML occurs in 80% of patients with TS.M/F ratio in this group is nearly equal. Although AML is considered benign,rare multicentric disease have been reported,regarding extension into renal v. ,IVC and deposits in the regional lymph nodes. Small AML lesions are asymptomatic,incidentally found on imaging studies.40% of cases have sign and symptoms of palpable abdominal mass,flank pain and hematuria.spontaneous hemorrhage in the tumor which may be occured in solitary AML,can present with acute abdomen and shock. AML of sufficient size may be appreciated on plain abdominal radiograph or an IVU as larg,extrarenal,exophytic component. The most ultrasonographic characterisitics of AML is hyperechogenicity,although not all AMLs are hyperechoic because of variability in fat content,hemorrhage,necrosis and caliceal dilatation. When negative attenuation values of less than 20 HU are recorded in renal tumors,AML may be reliably diagnosed in appropriate clinical setting.AMLs are usually well marginated,cortical heterogenous tumors.spiral CT followed by nephrogenic contrast-enhanced phase is ideal for characterization. Characterisitic appearance of AML with MRI include variable areas of high signal intensity on T1 and T2 weighed images.changes in signal intensity that occur as a result of intrinsic differences in resonant frequencies of processing photons are known as the chemical shift phenomenon.This phenomenon is more likely to demonstrate microscopic fat,such as that in RCC.Traditionally,AML has been diagnosed by comparing T1 images incorporating frequency-selective fat suppression with T1 images without frequency selective fat suppression. Significant finding of angiography in AML is lack of AV shunt.currently angiography is reserved for use in transcatheter embolization to control bleeding of AML.

References

1.Rakowski SK,Winterkorn EB,Paul E,Steele DJ,Halpern EF,Thiele EA.renal manifestation of tuberous sclerosis complex.kidney Int.Nov 2006;70(10) 2.Silverman SG,Pearson GD,Seltzer SE,Polger M,Tempany CM et al.small hyperechoic renal masses:comparision of helical and conventional CT for diagnosing angiomyolipoma.AJR AM J Roentgenol.oct 1996;167(4):877-810 3.Israel GM,Hindman N,Hecht E,krinsky G.The use of opposed-phase chemical shift MRI in the diagnosis of renal angiomyolipomasAJR AM J Roentgenol.jun 2005;184(6):1868-72

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