Biker's nodules L85.9

Rare, benign induration of the subcutaneous tissue in the perineal area as a result of repetitive local pressure and/or vibration, e.g. from bicycle saddles.

Mainly for cycling with high annual mileage. Overall rarely, exact data are missing. Probably clearly underdiagnosed.

In a study of extensive mountain biking 94% of the subjects showed sonographic abnormalities, in the control group only 16% (Frauscher F et al.).

Microtrauma by repetitive local pressure / vibration. Resulting collagen degeneration, myxoidal changes and low cell fibroblast proliferation ((Köhler P et al., Khedaoui R et al.).

Subcutaneous induration in the perineal area. Mostly unilateral, sometimes bilateral. Initially often recurrent, in the course of time persistent (Scheiba N et al. 2020)

All subcutaneous medium to slow-growing tumours, e.g. lipomas, epidermal cysts, adnexal tumours, periproctitic abscess, hernias, aneurysms, syringocele of the bulbourethral gland (cowper gland), malignomas/metastases.

Pressure relief, e.g. through cycling leave, alternatively ergonomic, soft saddle, changed riding position, recumbent bike.

In the case of pronounced findings, intralesional corticosteroids or hyaluronidase may be used.

Operative removal possible, cave recurrence due to poor pressure distribution with scarring possible.

1. Frauscher F et al (2001) US findings in the scrotum of extreme mountain bikers. Radiology 219:427-31.
2. Köhler P et al (2000) "Biker's nodule" - the perineal nodular induration of the cyclist. Dermatologist 51:763-5.
3. Khedaoui R et al (2014) Perineal nodular induration ("Biker's nodule"): report of two cases with fine-needle aspiration cytology and immunohistochemical study. Int J Surg Path. 22:71-5.
4. Scheiba N et al (2020) Perineal nodules caused by bicycling. Dtsch Arztebl Int 117:100.