Epithelioid angiomyolipoma: a rare variant of renal angiomyolipoma.

OBJECTIVE: We present a case of primary renal epithelioid angiomyolipoma, its association with tuberous sclerosis and review the literature.
METHODS: We present the case of a 12 year-old male with past medical history of tuberous sclerosis, characterized by developmental delay, tonic and clonic seizures, and cutaneous abnormalities. He presented with macroscopic hematuria and abdominal pain. CT scan of the abdomen showed the presence of a left renal tumor. He underwent left radical nephrectomy. Pathologic study of the specimen showed primary renal epithelioid angiomyolipoma, corroborated by immunohistochemistry staining. Review of the literature was performed for this rare variant and its malignant potential.
RESULTS: The presence of this epithelial variant is rare and must be taken into account because of its malignant potential and, thus, with different prognosis and follow up, compared to classical angiomyolipoma.
CONCLUSIONS: Renal angiomyolipoma is an uncommon benign tumor, representing a challenge for clinical and pathological diagnosis. Despite the big size they can reach, as well as bilaterality, multiplicity of lesions and/or lymphatic regional involvement, its malignant potential has not been established. Nevertheless, the epithelioid variant has been described recently, a rare entity with aggressive behavior, difficult histological characterization and poor prognosis.