Medial Distal Metaphyseal Femoral Irregularity in Children

Knee Lesion in a 62-year-old Woman

“…Usually, distal femoral cortical irregularity differs from malignant tumors by the absence of a soft tissue mass, the preservation of soft tissue planes, the absence of periosteal reaction, and the lack of associated warmth or local tenderness on physical examination [21]. Histologically, the absence of mitotic activity and pleomorphism will help distinguish it from sarcomas.…”

“…This is a benign entity that may have an atypical and aggressive appearance or a focal geographic radiolucency within the posterior cortex of medial femoral condyle. It typically occurs between the ages of 3 to 17 years, with a peak incidence at 10 to 15 years, and has been reported in 11.5% of boys and 3.6% of girls [21]. At epiphyseal closure, the irregularity decreases in size and often disappears, although it may persist into adulthood [7,9,13,20,27], as documented in one report in a 57-year-old man [17].…”

“…Some [21] consider it a developmental anomaly while others consider it an earlier phase of the more common fibrocortical defect [4,7]. Most lesions can be related to chronic traction or avulsive injury at the insertion of the extensor aspect of the adductor magus [2,5,9,14,20] or to the origin of the medial head of the gastrocnemius [7,17,20,23,26] and plantaris muscles [7].…”

“…Most lesions can be related to chronic traction or avulsive injury at the insertion of the extensor aspect of the adductor magus [2,5,9,14,20] or to the origin of the medial head of the gastrocnemius [7,17,20,23,26] and plantaris muscles [7]. Some authors, however, have not found tendinous attachments at this location [4,21,27]. In addition to the strong muscle pull exerted in this area, intense bone remodeling occurs simultaneously during periods of rapid skeletal growth.…”

“…The involved area is typically 1 to 2 cm in length, occasionally with reactive bone formation extending into the soft tissue [9]. Examination of both knees is recommended since the lesion is frequently bilateral (up to 35%) [21,26]. Additional imaging is sometimes required to differentiate this benign process from malignant bone and soft tissue tumors and, thus, CT and MRI are important imaging tools to ascertain anatomic relationship, bone destruction, and soft tissue involvement [22,23,26].…”