Renal Angiomyolipoma: The Good, the Bad, and the Ugly

Vos, Nicolas De; Oyen, Raymond

doi:10.5334/jbsr.1536

Cited by 87 publications

(116 citation statements)

References 35 publications

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“…Angiomyolipoma (AML) is an uncommon benign tumor with a prevalence between 0.2% and 0.6% [1]. It is histologically composed of fatty tissue, dysmorphic blood vessels and smooth muscle in varying proportions.…”

Section: Introductionmentioning

confidence: 99%

Renal angiomyolipoma-patient characteristics and treatment with focus on active surveillance

Lyrdal

Peeker

Lundstam

2020

Scandinavian Journal of Urology

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Objectives: To present a patient material of renal angiomyolipoma (AML) with focus on the risk of bleeding during active surveillance (AS). Methods: Medical records, 1999-2014, were studied and 98 patients (80 female, 18 men) with renal AML were identified. Eleven patients had tuberous sclerosis complex (TSC). Mean age was 54 (13-89) years. Results: Sixty patients (61%) were asymptomatic at presentation, 33 (34%) presented with flank pain and five (5%) with hematuria. Retroperitoneal bleeding or hematuria was diagnosed in 20 patients with a mean AML size of 74 mm (25-200 mm). Twenty-one patients were treated with angioembolization at time of diagnosis and 25 had surgery. Forty-five patients with sporadic AML (mean size 34 mm) and six with TSC (mean size 120 mm) were selected for AS. Only one patient with sporadic AML (46 mm) had a bleeding, whereas two of the six TSC patients had bleedings from three kidneys (AML 70-300 mm). In 25 patients (49%), the AML-size increased with 2.7 mm/year in sporadic and 5.4 mm/ year in TSC-associated AML. Thirteen patients were treated with AE (including all six TSC-patients) and five with surgery in 22 kidneys due to AML-size in 16, bleeding in four and suspicion of cancer in two. Conclusion: Bleeding occurred in 20% of AML at presentation. In patients selected for AS, we found a very low risk of bleeding in sporadic AML justifying our cut off size of 50 mm to trigger intervention. In TSC-associated AML individually tailored follow-up is needed due to a higher intervention rate.

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Section: Introductionmentioning

confidence: 99%

Renal angiomyolipoma-patient characteristics and treatment with focus on active surveillance

Lyrdal

Peeker

Lundstam

2020

Scandinavian Journal of Urology

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“…A subset of AMLs is more difficult to distinguish radiologically from renal cell carcinoma due to their low proportion of adipose tissue. 17 This subset of fat-poor AMLs is more likely to undergo percutaneous biopsy for assessment of malignancy. In some cases, the smooth muscle, fat, and blood vessel components are readily apparent, making the diagnosis of AML on a touch preparation slide straight forward.…”

Section: Discordant Diagnoses Resulting In False Positive Rosementioning

confidence: 99%

“…AMLs typically show a characteristic appearance on radiologic studies, due to the presence of mature adipose tissue, and can easily be distinguished from renal cell carcinomas. A subset of AMLs is more difficult to distinguish radiologically from renal cell carcinoma due to their low proportion of adipose tissue . This subset of fat‐poor AMLs is more likely to undergo percutaneous biopsy for assessment of malignancy.…”

Section: Discussionmentioning

confidence: 99%

Improving ROSE: Discrepant touch preparation and histology findings in cytology of renal masses: A 10‐year retrospective review

Shachner

Nodit

Hubbard

et al. 2019

Diagnostic Cytopathology

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Background The number of “renal incidentalomas” is on the rise due to increasing use of radiologic studies. Image‐guided core needle biopsies (CNB) with touch preparations are performed to guide specimen collection and triage of sample for additional studies. Results allow the clinical team to make appropriate treatment decisions. Design Our electronic database was searched for a 10‐year period to identify 180 image‐guided biopsies of renal masses with rapid on‐site evaluations (ROSE) and corresponding biopsy/resection specimens. Touch preparations were classified as non‐diagnostic, negative/benign, adequate/positive for malignancy/oncocytic predominance, or atypical. These results were compared to the final diagnosis on the biopsy or resection specimen (if available). Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were determined. Non‐diagnostic cases and cases in which ROSE and final diagnosis were discordant were reviewed by cytopathologists blinded to the original interpretation to reconcile discrepancies and highlight interpretation pitfalls. Results A ROSE diagnosis was rendered in 133 of 180 cases; 47 cases were non‐diagnostic. Of the 133 diagnostic cases, the ROSE diagnosis was concordant with the core biopsy final diagnosis in 125 cases, yielding a diagnostic accuracy of 94%. The overall sensitivity was calculated to be 80.1%; specificity 72.4%; positive predictive value 94%; and negative predictive value 41.2%. Conclusions Touch preparation slides are vital but imperfect tools in evaluating renal masses. In our study, distinction between malignant and benign samples was accomplished in most cases (94% accuracy), but there are limitations. Awareness of interpretation pitfalls allows informed decisions to be made regarding specimen collection and patient management.

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“…Larger tumors (>4 cm) can be symptomatic with flank pain and hematuria, or following retroperitoneal hemorrhage from intra-tumoral vessels. 8 The classic renal AML is a benign solid tumor which is typically composed of dysmorphic blood vessels, smooth muscle cells, and mature adipose tissue. These can show predominance of smooth muscle elements or adipose tissue, depending on which it can be labelled as leiomyoma-like or lipoma-like.…”

Section: Discussionmentioning

confidence: 99%

Epithelioid angiomyolipoma with tumor thrombus in IVC and right atrium

et al. 2020

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Epithelioid angiomyolipoma is an uncommon subtype of renal angiomyolipoma associated with potentially malignant behavior and is considered a distinct entity by the World Health Organization classification of renal tumors. We present a case of an epithelioid variant of angiomyolipoma with extension into the renal vein, inferior vena cava reaching up to the right atrium. Pre-operatively, a diagnosis of renal cell carcinoma was considered based on imaging findings. Intra-operatively due to extensive adhesions, surgical resection was not performed and only tissue sampling was performed for histopathology. Microscopic examination revealed short fascicles of spindle cells and perivascular epithelioid cells. A differential diagnosis of renal cell carcinoma with sarcomatoid differentiation was considered. The immunohistochemical profile showed tumor cells that express Melan-A and smooth muscle actin, while they were negative for pan-cytokeratin, PAX8, CK7, CD117 and CD34. Therefore a diagnosis of epithelioid angiomyolipoma was rendered. The presence of intravascular thrombi on radiological investigation and carcinoma-like growth pattern on light microscopy may compound an erroneous diagnosis of renal cell carcinoma. Hence, it is prudent for the urologist to consider differential diagnosis other than renal cell carcinoma when confronted with a renal neoplasm presenting with intravascular thrombi. In these cases, a core biopsy should be planned pre-operatively and diagnosis should be made with aid of appropriate immunohistochemical markers.

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Renal Angiomyolipoma: The Good, the Bad, and the Ugly

Cited by 87 publications

References 35 publications

Renal angiomyolipoma-patient characteristics and treatment with focus on active surveillance

Renal angiomyolipoma-patient characteristics and treatment with focus on active surveillance

Improving ROSE: Discrepant touch preparation and histology findings in cytology of renal masses: A 10‐year retrospective review

Epithelioid angiomyolipoma with tumor thrombus in IVC and right atrium

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