Premelanosome-negative inflammatory angiomyolipoma of liver with expression of cathepsin K and TFE3.

We report the first case of inflammatory variant of hepatic angiomyolipoma (AML) with expression of transcription factor E3 (TFE3) protein but negativity for HMB45 and melan A in a 62-year-old female. Imaging studies revealed a tumor in the left lobe of liver, sized 5.8 cm in maximum diameter. Microscopically, the lesion was composed of large polygonal or epithelioid cells with copious eosinophilic granular cytoplasm. There was a very prominent stromal lymphoplasmacytic infiltrate. Immunohistochemically, the tumor cells showed very strong and diffuse positivity for smooth muscle actin, and cathepsin K, while S-100 protein, keratin, desmin, HMB45 and Melan-A are negative. However, there was multifocal and very convincing nuclear positivity for TFE3, thus confirms the diagnosis.