[Biker's nodule"--perineal nodular induration of the cyclist].

The "biker's nodule" is a rarely appearing perineal nodular induration of the cyclist. Repeated microtrauma to the subcutaneous fatty tissue or collageneous tissue, caused by pressure or vibration which the bicycle's saddle exerts on the perineal region, leads to collagenous degeneration, myxoid alteration and pseudocyst formation. Because of the painful subcutaneous nodules the patient is often forced to reduce or even give up his training. Therapy of the "biker's nodule" consists in avoiding the pathogenetic factors, i.e. giving up training for a temporary period of time and reducing pressure on the perineal region. Intralesional injection of either hyaluronidase or corticosteroids may also be helpful.