A 29-year-old female patient presented with 1 x 1 cm sized subcutaneous nodule on the left forearm for 2 months. The patient had no history of trauma, and the mass had not increased in size over 2 months. At first, the skin lesion was considered as lipoma or other benign skin neoplasm. On the sonographic examination, there was 0.7 x 0.5 cm sized relatively well defined isoechoic hypervascular nodule in the soft tissue overlying forearm. Also, Doppler sonography revealed increased vascularity in the mass. Surgical total excision was performed. Histopathological examination showed intravascular thrombus with organization and reactive proliferation of capillary endothelium. Finally, she was diagnosed as Intravascular papillary endothelial hyperplasia (IPEH). There was no remnant lesion and the postoperative course was satisfactory during 6 months follow up. Intravascular papillary endothelial hyperplasia (IPEH), also known as Masson’s tumor, is a rare neoplasm of vascular origin. In the histopathological examination, it is characterized by a papillary proliferation of endothelial cells associated with thrombotic material. Treatment consists of complete resection of the tumor. Herein, we report a rare case of intravascular papillary endothelial hyperplasia mimicking lipoma occuring on the upper extremity.