Going breakdancing today? If so, maybe go easy on the headspins. Unless you want to end up with a “cone-head”, that is.

Breakdancing’s extreme physical demands mean it is known to involve a high risk of injury: everything from hair loss to sprains and damage to almost every part of the anatomy.

But now breakdancing enthusiasts have been warned of a new danger: that spinning on their heads too much could lead to them developing a sizeable protrusion on top of their head.

This has emerged as a potential hazard in a case report in a leading medical journal about a man in his 30s in Denmark who developed such a visible lump on his head, as a result of undertaking breakdancing training up to five times a week for 19 years, that he had surgery to remove it.

It grew as a result of what breakdancers call “headspin hole” or “breakdance bulge”, which BMJ Case Reports describes as “a unique overuse injury in breakdancers caused by repetitive headspins”.

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Doctors initially considered a number of possible diagnoses, including that the bulge could be cancer or a benign tumour.

An MRI scan showed that it was what the authors of the case report call “a subgaleal mass measuring 34cm x 0.6cm x 2.9cm near the midline vertex”.

It turned out to be an extreme example of the lump on the scalp that “headspin hole” can involve. “In radiologic descriptions, the term ‘cone-head sign’ is used,” the doctors write.