Learning objectives
-brief reminder of a benign,
but sometimes aggressive pathology: renal AML (angiomyolipoma),
resembling malignancy due to its IVC (inferior vena cava) extension;
-listing the main features of AMLs,
depending on the imaging technique;
-discussing complications and treatment options in AMLs;
-recognizing the IVC filling defects;
-listing the main differential diagnoses (renal neoplasms and other cancers that invade IVC) and illustrating their radiological findings.
Background
Tumoral invasion of IVC is a life-threatening condition.
Most often a feature of malignant pathology has to be confirmed and characterised by imaging.
In rare circumstances benign tumors can also extend into IVC,
behavior which mimics malignancy.
On rare occasions renal AMLs may show extension into renal vein and IVC.
The intravascular extension of this fatty lesion indicates an aggressive element.
Definition:
Renal AML is a benign tumor of the kidneys.
Typically it is a solid tumor composed of varying amounts of 3 elements: mature...
Findings and procedure details
Aggressive angiomiolipoma
At times,
AMLs may show extension into venous structures (renal vein and IVC).
The first case of aggressive AML was reported by Kutcher et al in 1982.
Between 1982 and 2013 approximately 43 similar cases were reported [10].
Imaging not only helps in tumor diagnosis,
but also in preoperative assessment.
Case 1
A 58-year-old female patient was addressed to the urology department accusing flank pain and hematuria.
No relevant medical history.
Abdominal US showed a well defined,
hyperechoic mass in the right kidney,...
Conclusion
CT and MRI are very accurate imaging techniques in evaluating the kidneys or other retroperitoneal tumors and appreciating their IVC invasion; the radiologist is required to narrow the diagnosis by differentiating these lesions (benign/ malignant,
primary/ secondary) and to assess their extension,
impacting directly their staging and treatment planning.
We must keep in mind that IVC extension is not always the result of a malignancy,
no matter how “aggressive” it may look; a gross tumor showing macroscopic fat on CT or MRI should raise suspicion...
References
1.Jinzaki M,
Silverman SG,
Akita H,
Nagashima Y,
Mikami S,
Oya M.
Renal angiomyolipoma: a radiological classification and update on recent developments in diagnosis and management.
Abdom Imaging.
2014 Jun; 39(3): 588-604.
2.Eble JN,
Sauter G,
Epstein JI,
Sesterhenn IA.
World Health Organization classification of tumors: pathology and genetics.Tumors of the urinary system and male genital organs.
Lyon" IARC Press.
2004.
3.Renal angiomyolipoma,
online article available at: https://radiopaedia.org/articles/renal-angiomyolipoma.
4.Dhyani M,
Katz D,
Udeshi M,
Kurup A,
Samir A.
Benign,
malignant and cystic focal renal lesions....