A Review of Angiomyolipoma and Its Morphological Variants

Abstract

Angiomyolipoma (AML) is defined as a benign clonal neoplasm composed of thick-walled blood vessels, smooth muscle cells and adipose tissue, belonging to the family of perivascular epithelioid cell tumors (PEComa). Morphologic variants of AML are composed of variable proportions of mature adipose tissue, thick-walled, poorly organized blood vessels, smooth muscle with or without feature of atypia and/or pleomorphism. Similar to all PEComas, AML demonstrates co-expression of melanocytic and smooth muscle markers, but negative for cytokeratin. This paper explores AML and its variants with the goal of distinguishing between these morphologic variants, and differentiating them from other renal malignancies.