Cortical desmoid

Cortical desmoid is a benign, self-limiting condition that typically occurs at the posterior medial aspect of the distal femur. It is most commonly observed in adolescents and young adults, particularly those who are active or involved in sports. Despite its name, a cortical desmoid is not a true tumor; rather, it is a fibro-osseous lesion that represents a localized area of cortical irregularity or erosion. The condition is also known as a distal femoral cortical irregularity (DFCI).

Etiology

The exact cause of cortical desmoid is not well understood, but it is believed to be related to stress or trauma to the area, possibly due to repetitive microtrauma from muscle attachments, which leads to an overgrowth of fibrous tissue. This is supported by its common occurrence in individuals who are physically active.

Symptoms and Diagnosis

Cortical desmoid is often asymptomatic and is usually discovered incidentally on radiographs taken for other reasons. When symptoms do occur, they may include mild localized pain or discomfort. On radiographic examination, a cortical desmoid appears as a well-defined, radiolucent lesion with sclerotic borders, located on the posterior aspect of the distal femoral metaphysis.

Magnetic resonance imaging (MRI) can be used to further evaluate the lesion, which typically shows low signal intensity on T1-weighted images and variable signal intensity on T2-weighted images. MRI is particularly useful in distinguishing cortical desmoids from more serious conditions such as osteosarcoma.

Treatment

Given its benign nature and tendency to resolve on its own, treatment for cortical desmoid is usually conservative. Management strategies may include observation, rest, and analgesics for pain relief if necessary. In most cases, the lesion stabilizes or regresses over time without the need for intervention.

Prognosis

The prognosis for individuals with a cortical desmoid is excellent. The condition does not progress to malignancy, and symptoms, if present, are typically mild and self-limiting. With conservative management, most individuals experience resolution of symptoms and stabilization of the lesion.

Epidemiology

Cortical desmoid is most commonly seen in adolescents and young adults, with a slight male predominance. It is associated with physical activity, particularly sports that involve running or jumping.

See Also

• Bone tumor
• Fibrous dysplasia
• Osteochondroma