47 year old female with pain. Evaluate for right third ulnar proximal nailbed glomus tumor. A marker was placed along the dorsal and ulnar aspect of the middle phalanx at the level of the DIP joint. Deep to the marker, is curvilinear enhancement along the lower margin of the DIP joint and head of the middle phalanx that measures approximately 5 mm in the AP dimension. This curvilinear focus of enhancement is of low to intermediate signal intensity on T1-weighted imaging and is of intermediate to slightly increased signal intensity on T2-weighted imaging. It lies deep to the ulnar collateral ligament. The ulnar collateral ligament itself appears slightly thickened and its attachment to the base of the distal phalanx is indistinct, which may represent a tear. There may also be slight scalloping of the underlying medial aspect of the head of the middle phalanx, but this is equivocal. The radial collateral ligament appears normal. The remaining bones appear normal. The PIP joint appears normal. The flexor and extensor tendon apparati appear normal.
Although no discrete mass is seen, there is peculiar curvilinear enhancement along the medial aspect of the DIP joint and head of the middle phalanx of uncertain etiology or significance. It may represent a focal synovitis, but would be an unusual morphology for a glomus tumor. The overlying ulnar collateral ligament also appears slightly thickened and its attachment to the distal phalanx is indistinct on coronal images, suggesting the possibility of a tear.