"Headspin hole": Man develops a benign tumor over a foot long and more than an inch thick after decades of breakdancing.

I quoted the second half the article.

"Headspin hole": Man develops foot-long scalp tumor after decades of breakdancing | CNN

[There is] a condition known in the breaking community as headspin hole, an overuse injury that can affect the scalp. The condition typically begins with hair loss but can develop into a significant bump on the top of the head. In the case report, published Thursday in the medical journal BMJ, a man in his early 30s who had been breaking for nearly 20 years was treated for a benign tumor that had grown over a foot long and more than an inch thick.

The condition, sometimes referred to as breakdance bulge, is thought to be caused by repeated friction between the scalp and the floor during headspins, compounded by the pressure exerted during the move.

“We believe the condition results from repeated friction between the head and the floor, combined with the weight-bearing nature of headspins, accumulated over years of breakdancing,” said Dr. Christian Baastrup Søndergaard, a neurosurgery specialist at Rigshospitalet in Copenhagen. “This repetitive strain on the skull, scalp and skin likely triggers inflammation, and over time, minor bleeding may lead to thickened skin and scar tissue, forming the characteristic bulge.” Søndergaard, a co-author of the case report, treated the patient.

The patient reported discomfort and soreness, and said he avoided public outings without a hat to conceal the bump. After surgeons removed the growth, the patient expressed relief: “It’s great to be able to go out in public without a cap or hat. Many people tell me they don’t notice the bump anymore and that my head looks completely normal.”

Despite some awareness of the condition within the breaking community, medical literature on “headspin hole” remains limited, according to the case report. Users on Reddit’s r/bboy community, an online forum for breakers, have discussed developing bald spots over time and shared tips like wearing padded beanies or adding gel pads under a hat while performing the maneuver.