Renal Epithelioid Angiomyolipoma: A Case Report

Angiomyolipoma (AML) is a rare benign mesenchymal tumor, constituting less than 10% of renal masses, and occurs sporadically or in association with tuberous sclerosis complex (TSC). AML is generally categorized into classic AML and epithelioid angiomyolipoma (EAML), with the latter comprising approximately 4.6% of AML cases. EAML is characterized by a predominance of epithelioid cells, minimal adipose tissue, and distinct histological features such as necrosis and potential malignancy, which can lead to misdiagnosis as renal cell carcinoma (RCC). This report presents a case of renal EAML in a 27-year-old Iranian woman with mild left flank pain and hematuria, with imaging studies revealing an echogenic mass in the left kidney suggestive of AML. Contrast-enhanced computed tomography and magnetic resonance imaging confirmed a heterogeneous mass with fat content. Histopathological examination post-partial nephrectomy revealed a carcinoma-like lesion with a proliferation of epithelioid cells, necrosis, and scattered giant cells, consistent with EAML. Notably, the tumor exhibited low mitotic activity and lacked atypical mitoses, confirming its benign nature. Despite the rarity of EAML and the lack of distinct clinical or radiological features, this case underscores the importance of pathological findings for accurate diagnosis. The management of EAML remains challenging due to its aggressive potential; however, surgical intervention is often the gold standard treatment. This case contributes to the limited literature on EAML, emphasizing the need for further research to establish definitive diagnostic criteria and treatment guidelines to address its clinical uncertainties.