Biker's nodule

Last revised by Liz Silverstone on 16 Sep 2023

Biker's nodule refers to a mass in the perineum that occur in cyclists. 

Epidemiology

In keeping with bicycling being a male dominated recreational activity, the pathology is most commonly found in young-middle aged males, more commonly during first 6 to 12 months of taking up the sport.

Pathology

Chronic pressure and friction in perineal region between a bicycle saddle and inferior ischial tuberosities can result in delamination changes of fat in the ischiorectal fossae. Over a longer term in some cyclists, granulation tissue formation and fibrosis ensues.

Radiographic features

Depending on the stage at which imaging is performed, the degree of edema, inflammation or fibrosis can vary, and so do imaging findings.

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