Knee intra-articular extraskeletal aneurysmal bone cyst: a case report and review of literature

We report a case of a 12-year-old female with no history of trauma who presented with knee pain. Imaging studies revealed an infrapatellar mass that was fast to calcify during a period of 3  months. MRI showed high T2 center, low T1 signal, and heterogenic enhancement with a rim of low intensity consistent with calcified boarders surrounded by severe soft tissue edema. The lesion was surgically excised, and a histological examination revealed an aneurysmal bone cyst possibly arising w ithin myositis ossificans or heterotopic ossification. In her last follow-up 1.5 years after the surgical excision, the patient was symptom free and without signs of recurrence. To the best of our knowledge, this is the first reported case of an intra-articular ESABC located in the knee.

Source: Skeletal Radiology - August 22, 2020 Category: Radiology Source Type: research