7. Soft tissue Masses: DON'T Touch Lesions

Question 1

Answer 1

Myositis Ossificans

Circumferential calcifications with a lucent center

Can look scary on MRI if imaged early because of edema, and avid enhancement

Question 2

Avulsion Injury

Answer 2

Typical location near the pelvis

Question 3

Answer 3

Avulsion Injury

Can have an aggressive periosteal reaction

Question 4

Answer 4

Cortical Desmoid

Characteristic location on the posterior medial epicondyle of the distal femur. Bilateral 30% of the time

Can be hot on bone scan.
NOT a desmoid (despite the name). It’s actually a tug lesion from the medial gastrocnemius and ADDuctor magnus.

Question 5

Answer 5

Synovial Herniation Pit “Pitt’s Pit”

Anteroposterior femoral neck

Lytic appearing lesion

Associated with femoral acetabular impingement syndrome (probably).