A solitary metastatic lung tumor slow-growing with late onset from renal epithelioid angiomyolipoma

We report the case of a 46-year-old Japanese woman with past medical history of right nephrectomy for as sarcomatoid renal cell carcinoma 14 years earlier. A pulmonary nodule was detected in the left upper lobe 7 years after nephrectomy and it had grown slowly for 6 years. We performed wedge resection for the tumor because we suspected that the nodule was metastasis from the renal tumor. But the nodule was diagnosed as epithelioid angiomyolipoma since the nodule was positive for HMB-45 and negative for epithelial markers and S-100 protein by immunohistochemical analysis. Therefore her disease was revised as a solitary pulmonary metastasis from renal epithelioid angiomyolipoma. Epithelioid angiomyolipoma is potential malignant mesenchymal tumor because the tumor recurs or metastasizes, and progresses rapidly on one-third of the cases. This case is the first report that the disease was stable for a long time after late recurrence caused.