Evolution of gout: "malignant" change over time?

Gout is a common entity; yet it is such a great mimicker in its imaging features that it can confuse clinicians and radiologists alike, sometimes leading to unnecessary investigations and treatment. We present a case of a 52 year old male renal transplant patient who presented with a slow growing mass in his left shin. The initial radiograph demonstrated a non-aggressive looking calcified lesion. A fine needle aspiration demonstrated this lesion to be gout deposition. The lesion was unchanged in the following eight years until the patient reported a sudden growth in size. Imaging showed features of an aggressive lesion with disruption of the previous calcification as well as enhancement on magnetic resonance imaging. Surgical excision biopsy was performed in view of the worrisome features on imaging and the histology showed tophaceous gout. Following description of our case, we reviewed the clinical and imaging features of gout and discussed its differential diagnoses.