A massive renal epithelioid angiomyolipoma with multiple metastatic lymph nodes

Abstract

A 47-year-old man presented with dull pain in the left upper abdomen for 1 year. Computed tomograph (CT) examination revealed a very large heterogeneously enhancing mass in the left kidney, measuring up to 28 cm. The mass was accompanied by several enlarged lymph nodes in the peri-aortic region. Radical nephrectomy was performed and pathologic evaluation revealed sheets of epithelioid cells and piecemeal necrosis consistent with malignant epithelioid angiomyolipoma (EAML) with regional lymph node metastases. The tumor cells were strongly positive for human melanosome-associated protein (HMB-45) on immunohistochemical staining. There was neither metastasis nor recurrence 2 years postoperatively. EAML is a rare tumor of mesenchymal tissue with potential for aggressive behavior. If this neoplasm is suspected based on CT features, EAML should be confirmed by pathology and immunohistochemistry.

Introduction

Epithelioid angiomyolipoma (EAML) is an unusual type of mesenchymal neoplasms which mainly occurs in the kidney. EAMLs often resemble sarcomatoid renal cell carcinoma (RCC), high-grade RCC, or sarcomas. So far, only a small number of cases of EAML have been recorded. Herein we report the case of a 47-year-old woman with a massive left renal tumor that radiographically was suggestive for renal sarcoma or RCC due to the absence of fat content with multiple enlarged lymph nodes. After nephrectomy, pathology confirmed the diagnosis of EAML.