Malignant epithelioid angiomyolipoma of the kidney with pulmonary metastases and p53 gene mutation

Angiomyolipoma (AML) is a rare tumor mainly arising in the kidney. Here we report the case of a 55-year-old woman with malignant epithelioid angiomyolipoma with p53 gene mutation. After 7 years from radical nephrectomy of the left kidney, the patient developed multiple lung metastases that showed morphologic features overlapping those of the previously lesion, which was misdiagnosed as renal cell carcinoma. Both renal and pulmonary tumors were reevaluated by immunohistochemical assay, which were showed positive for HMB-45 and p53 protein (95%), but negative for epithelial markers and S-100 protein. A correct diagnosis of malignant epithelioid angiomyolipoma was made on the basis of those results. Meanwhile exon 8 mutation of p53 gene was detected in the renal tumor by microdissection-PCR-SSCP and sequencing technique indicating that p53 gene mutation may play an important role in malignant transformation. The patient was died of respiratory failure after 15 years' follow-up. This is the second report of renal malignant angiomyolipoma with p53 gene mutation.