Figure 3b. Dactylitis in a 39-year-old man with sarcoidosis and hyperuricemia. (a) Posteroanterior radiograph of the hand shows eccentric swelling about the fifth digit. A faint erosion or cyst is seen at the medial margin of the proximal middle phalanx, along with cortical erosion in the distal phalanx. Gout was the favored radiologic diagnosis, but needle aspiration biopsy was not diagnostic. (b) Axial proton-density-weighted MR image (2,600/15) demonstrates low-signal-intensity material in the soft tissues about the second and fifth digits and extending into the medullary cavity of the fifth middle phalanx. (c-e) On axial fat-saturated T2-weighted (3,000/90) (c), coronal T1-weighted (450/10) (d), and coronal fat-saturated intermediate-density-weighted (1,600/16) (e) MR images, the paraosseous material remains low in signal intensity (arrows in d and e). A cystlike lesion whose contents demonstrate increased signal intensity is noted at the base of the fifth middle phalanx (arrowhead in e).