Perineal Nodular Induration (Cyclist's Nodule).

Perineal nodular induration, also called Cyclist's nodule, is an uncommon, benign pseudotumour of the perineal soft tissues that arises almost exclusively in individuals who engage in prolonged saddle-based sports, most notably road cycling. It is thought to result from chronic mechanical microtrauma-pressure, vibration, and shear-transmitted between the ischial tuberosities and a hard saddle. Management includes prolonged rest from cycling, bike-fit and behavioural modification, intralesional corticosteroid injection, or surgical excision for refractory disease.

Abstract from PubMed