Popliteal pterygium: report of an anatomic variant.

The presence of a vertical fibrous cord along the posterior lower extremity is highly unusual. Because of its inflexible nature, cord structure may greatly limit leg extension, dorsiflexion, and general ambulation. Because of the paucity of such events, management strategies remain poorly defined. Although preoperative magnetic resonance imaging is useful in defining cord anatomy, a great deal of caution is critical during cord dissection. Not only have popliteal vessels been incorporated into such defects, but reports describe tibial nerve involvement as well. Although vertical fibrous cord presence is exceedingly rare in the lower extremity, fibrous cording is a frequent component of popliteal pterygia. However, the present malformation did not include soft tissue webbing, a critical portion of pterygial structure, and therefore cannot be considered a true pterygium. Although we suspect that the present cord defect may represent a relatively minor pterygial presentation, development of these unusual malformations remains enigmatic and confirmation is not currently possible. Here, we present an unusual case of vertical fibrous cord development in the lower extremity, and discuss relevant aspects of management.