Age / Sex : 78 / M

Chief complaint : Intermittent swelling of hand


What is your diagnosis?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer)

Courtesy :  김완태 (Wan Tae Kim), 중앙보훈병원 (Veterans Health Service Medical Center)

Extensor digitorum brevis manus muscle (Accessory muscle)

Discussion

Findings
1. Soft tissue mass like lesion within the extensor compartment at the the level of the carpometacarpal joint with homogenous low-to-intermediate signal intensity which was isointense to skeletal muscle on T1WI and T2WI.
2. No significant contrast enhancement.

References
1. Extensor Digitorum Brevis Manus presenting as a symptomatic lump on the dorsum of the hand. Shekhar SK, Paddock M, Kotnis N. Radiol Case Rep. 2020 Sep 10;15(11):2271-2274.
2. Accessory muscles: anatomy, symptoms, and radiologic evaluation. Sookur PA, Naraghi AM, Bleakney RR, Jalan R, Chan O, White LM. Radiographics. 2008 Mar-Apr;28(2):481-99.