68-year-old male with pain since 2008, occasional trigger. Evaluate for tenosynovitis or mass of the left thumb There is a multilobulated collection of near fluid signal intensity at the level of the base of the first and second metacarpals, deep to the first dorsal interosseous muscle, either within or along the dorsal surface of the adductor pollicis, adjacent to the dorsal carpal branch of the radial artery, measuring 8 x 5 mm in the transverse dimension and 14 mm in the craniocaudal dimension. We suspect that this represents a ganglion. Proximally, the mass abuts the base of the first metacarpal and tapers distally. The signal intensity of the bone itself is normal. The tendons, including that of the flexor pollicis longus appear normal. We see no findings to suggest a pulley tear.
Small multilobulated mass adjacent to the radial aspect of the base of the second metacarpal likely representing a ganglion. The tendons appear normal.