Case of renal myxoma.

Renal myxomas are rare neoplasms. Only three cases have been convincingly diagnosed as renal myxoma. Here we report an additional case. The case was a 36-year-old man and he was discovered incidentally at the regular health-check for chronic hepatitis B. Computed tomography showed 8 cm low-density tumor in the lower pole of the left kidney. The tumor was slightly enhanced by contrast agents. Magnetic resonance imaging revealed the tumor as low intensity on T(1)-weighted imaging and high intensity on T(2)-weighted images. The tumor was enhanced by gadrinium enhancement homogeneously. The resected kidney contained semitranslucent, gelatinous, tan mass within the lower pole of the kidney. The microscopic examination showed the typical appearance of a myxoma, which consisted of large amounts of myxoid material containing a few uniformly scattered spindle cells The tumor cells showed immunoreactivity for vimentin but not for S-100 protein, epithelial membrane antigen, cytokeratin, alpha smooth muscle actin.