Abstract
Knuckle pads are benign subcutaneous fibrotic plaques. Clinically, these lesions present as slowly enlarging, painless and mobile nodules, typically located at the extensor site of the proximal interphalangeal (PIP) and metacarpophalangeal (MCP) joints. On ultrasound, knuckle pads present as subcutaneous hypoechogenic nodular thickenings. These lesions have a low to intermediate signal intensity on T1-WI and T2-WI MRI. Solely on the clinical presentation and the typical location, the diagnosis of knuckle pads can be made, however the radiologist has to be aware of the imaging features of knuckle pads to avoid misdiagnosis and potentially harmful treatment.