An unusual incidental finding

摘要

A 63-year-old man presented with weight loss and rectal bleeding. He had no significant medical history and was taking no medications. He complained of some minor left hip pain, which had been attributed to osteoarthritis. Physical examination was normal. The patient's blood count, renal function and liver enzymes were normal. The carcinoembryonic antigen level was elevated. Colonoscopy revealed a small polypoidal tumour in the descending colon. Biopsies were positive for colonic adenocarcinoma. As part of the staging process, CT of the thorax, abdomen and pelvis was performed, which was unable to depict the primary tumour and showed no nodal disease or metastasis. However, the proximal left femur was abnormal. Subsequently, plain radiography and MRI of this region were undertaken (Figures 1-3). What is the diagnosis? Is there any clinical implication?