Epithelioid Hemangioendothelioma in the Area of the Neurovascular Bundle of the Upper Arm Mimicking a Schwannoma of the Ulnar Nerve.

Epithelioid hemangioendothelioma (EH) is a rare vascular malignant sarcoma. To date, there are only two published case reports of EH mimicking nerve sheath tumors of a peripheral nerve. A 41-year-old woman presented with a painful node on the inside of the upper arm and motor deficits of the ulnar nerve. Magnetic resonance imaging (MRI) follow-up and neurosonography revealed a slowly progressive, contrast-enhancing tumor in the area of the neurovascular bundle. A schwannoma of the ulnar nerve was suspected. At surgery, the tumor was adherent to the brachial artery, but not to nerves. Pathology revealed an EH. EH may mimic a nerve sheath tumor and should be taken into consideration, especially because of its potential for metastasis and fatal progression.