Promontory sign in a reactive benign vascular proliferation.

The promontory sign was described 27 years ago and it was claimed to be useful in the diagnosis of early stages of Kaposi sarcoma. However, it is not pathognomonic, because it has also been described in angiosarcoma and in benign vascular tumors. Some authors claim that some reactive vascular lesions known as pseudo-Kaposi do not present the promontory sign. We report the case of a vascular cutaneous lesion on the breast of a 75-year-old woman, which had a benign clinical behavior, and presented with the promontory sign. The lesion was made of tortuous dilated lymphatic tissue, and small capillaries with a lobular distribution. It was characterized by CD31 and D240 immunostaining, although no immunostaining for human herpesvirus 8 (HHV8) was found. The lesion spontaneously improved and eventually disappeared. It was thought to be secondary to a chronic trauma to the area due to a prolonged stance in bed in the emergency room.