Metastatic adenocarcinoma of the colon presenting as a monarthritis of the hip in a young patient

BACKGROUND Malignant arthritis is a rare manifestation of metastatic disease. We describe the case of a previously well 28 year old man in whom hip pain was the presenting symptom of disease. We describe the case and discuss the aetiology of colorectal cancer in young patients. We then review the literature and discuss the investigation and management of malignant joint arthritis. CASE PRESENTATION We present the case of a 28 year old man who presented to the emergency department with an acute monoarthritis of the hip. He had an unremarkable past medical history and was systemically well. A diagnosis of malignant joint effusion was reached after a heightened index of clinical suspicion, magnetic resonance imaging and cytological evaluation of the synovial fluid. Computed tomography and bone scan confirmed widespread metastatic disease from a primary colonic adenocarcinoma. The patient tolerated three cycles of oxaliplatin and capecitabine but died 4 months after presentation. CONCLUSION The metastatic spread of cancer to the joint and the synovium is one of the rarest manifestations of malignant disease and has not been previously reported as the presenting symptom of disease. The diagnosis is a difficult one to reach and is associated with a poor prognosis. This case illustrates the importance of thorough investigation in reaching this diagnosis and entertaining the possibility in individuals who do not respond to conventional management of acute monoarthritis, even in young patients and individuals who do not display any other symptoms of disease.