Clinical Presentation and Treatment outcomes of Benign Renal Tumor: Angiomyolipoma

Abstract

Background: Angiomyolipoma (AML) is a benign renal neoplasm composed of abnormal blood vessels, smooth muscle cells, and adipose tissue. About 40% of AMLs present with acute severe hemorrhage and is a potentially life-threatening condition. The risk of bleeding is proportional to tumor size and increasing significantly with size above 4 cm. Therefore, the patients with AMLs of 4 cm or more or spontaneous rupture of AMLs need interventional or surgical treatment. Objective: To evaluate the clinical presentation and treatment outcomes of the AMLs. Materials and Methods: The present report was a retrospective analytic study of the medical records and imaging studies in Phramongkutklao Hospital between January 2002 and December 2019. Results: Sixty-three patients, with a female:male ratio of 47:6, and a median age of 54.76 years with a range of 8 to 84 years, were included in the present analysis. Seven (11.1%) had tuberous sclerosis complex (TSC) and 56 (88.9%) had sporadic. Fifty-four had a solitary lesion, whereas nine had bilateral lesions. Asymptomatic AMLs were 50 (79.4%) and symptomatic AMLs were 13 (20.7%). There were 46 (73.0%) AMLs smaller than 4 cm and 17 (27.0%) AMLs of 4 cm or larger. AMLs smaller than 4 cm were incidentally discovered (n=40, 87%) and revealed due to symptoms such as flank pain (n=3, 6.5%) and hematuria (n=3, 6.5%). AMLs of 4 cm or larger were incidentally discovered (n=10, 58.8%) and revealed due to symptoms such as flank pain (n=7, 41.2%) and not presented with hematuria. AMLs smaller than 4 cm were mostly treated by follow up (n=39, 84.78%) or surgery (n=7, 15.22). AMLs of 4 cm or larger were treated by follow-up (n=11, 64.7%) then converted to arterial embolization (n=4, 23.5%) and converted to surgery (n=8, 47.1%). Two AMLs of 4 cm or larger died (11.8%). Conclusion: Significant differences in clinical manifestations and treatment outcomes were noted in respect to tumor characteristics, association with TSC, and treatment modality. Considering the benign nature of AML, size, and association with TSC ought to be considered when deciding upon active surveillance or prophylactic intervention. Keywords: Angiomyolipoma; Tuberous sclerosis complex; Embolization; Nephrectomy