Malignant clear cell "sugar" tumor of the kidney: Clear cell variant of epithelioid angiomyolipoma

Angiomyolipoma is a heterogeneous proliferation composed of an admixture of blood vessels, smooth muscle cells, adipocytes and peculiar myoid cells with variable melanin synthesis. Epithelioid angiomyolipoma, which often has malignant potential, has been reported previously.(1) Recently clear cell "sugar" tumor has been described as a clear cell variant of epithelioid angiomyolipoma.(2) Clear cell "sugar" tumor or epithelioid angiomyolipoma of the kidney is microscopically similar to renal cell carcinoma and, therefore, differential diagnosis is often difficult.(2) However, the habitual presence of melanosomes in these lesions is significant and distinguishes them from renal cell carcinoma.(1) We report a case of clear cell "sugar" tumor that consisted of pigmented clear cells resembling renal cell carcinoma.