An unusual gum lesion with a positive pregnancy test

A previously well 46 year old woman presented to her dentist with toothache. She was otherwise asymptomatic. On examination, the dentist noticed a bleeding lesion in the left upper gum (fig 1⇓). In the middle of the examination, she felt warm, flushed, and faint; she briefly became unconscious but rapidly recovered with no evidence of convulsions or other problems. An ambulance was nevertheless called. In the emergency department her pulse, blood pressure, respiratory rate, and temperature were normal but the odd gum lesion was again noted. To her surprise, a routine pregnancy test before chest radiography was positive. She had experienced irregular light periods for the previous few months. The date of her last menstrual period was unknown, and she had been using no regular contraception. Because she had two children aged 5 and 7 years, it was assumed that she might be pregnant again. Radiography was deferred and she underwent an ultrasound of her pelvis, which showed a large vascular uterus with no viable pregnancy. Her serum human chorionic gonadotrophin concentration was 343 255 IU/L (reference value <5 IU/L). After exclusion of a viable pregnancy, chest radiography was performed and showed multiple lung lesions. An urgent computed tomography scan of the whole body showed a large vascular uterine mass together with lesions within the kidney, liver, lungs (fig 2⇓), and both cerebral hemispheres.