Clinical Characteristics and Surgical Outcomes of Renal Epithelioid Angiomyolipoma: A Comparison with the Classic Type

Abstract

Objective: To compare clinical characteristics and surgical outcomes between patients with epithelioid angiomyolipoma (EAML) and classic angiomyolipoma (AML), and to identify factors associated with EAML diagnosis. Materials and Methods: All patients with renal AML who underwent surgery at Siriraj Hospital between January 2013 and December 2024 were reviewed. Clinical features and surgical outcomes were compared between patients with classic AML and those with EAML, and predictors of EAML were evaluated using multivariable analyses. Results: Among 116 eligible patients, 101 had classic AML and 15 had EAML (12.9%). Most patients were female and were diagnosed in their fifth decade. Demographics, tumor laterality, prevalence of tuberous sclerosis complex gene mutation, and comorbidities did not differ between the 2 groups. Palpable mass (26.7%) and hematuria (13.3%) were more frequent in patients with EAML than in those with classic AML. Most patients with EAML underwent radical or partial nephrectomy due to suspected malignancy. In multivariable analysis, tumor size ≥ 10 cm (odds ratio 15.44; P = 0.003) and a radiologic impression of cancer (odds ratio 46.98; P < 0.001) independently predicted EAML. Four patients with EAML had adverse pathologic features and experienced poor survival; 3 patients died with metastases. The 3-year overall survival was 100% in classic AML and 76.9% in EAML (P < 0.001). Conclusions: Patients with EAML had less favorable surgical outcomes than those with classic AML. Larger tumor size and a preoperative radiologic impression of malignancy were associated with an EAML diagnosis. Adverse pathologic features in EAML suggest malignant potential.