63-year-old male with painful mass and localized swelling on the dorsal aspect of the right small finger metacarpophalangeal joint for 6 weeks. There is a mass within the soft tissues dorsal to the fifth metacarpal head. The mass insinuates between the extensor tendons of the fifth finger. The tendons appear normal.The mass is fluid signal intensity, showing only peripheral enhancement following gadolinium administration. There is little if any edema in the adjacent soft tissues and we see no frank destruction of the underlying bone.There appears to be very mild synovitis of the underlying fifth metacarpophalangeal joint, with small focus of abnormal subchondral signal intensity in the fifth metacarpal head. On the large field of view coronal images, rounded foci of signal abnormality are also seen within the second, third, and fourth metacarpal heads with narrowing of the second metacarpophalangeal joint associated with mild synovitis.The radial collateral ligament of the fifth metacarpophalangeal joint is indistinct and thickened, which may reflect a sprain or tear. Radial collateral ligament of the second metacarpophalangeal joint is also likewise indistinct and may be torn.
1.Peripherally enhancing mass of fluid signal intensity dorsal to the fifth metacarpal head, which may represent a ganglion or perhaps a synovial lined fluid collection. The relative absence of adjacent soft tissue edema argues against abscess.2.Other findings as above.