A rare medical condition has made a man's head look like his brain is on the outside, according to a case study.

A 21-year-old man from Brazil has been left with folds and holes in his scalp, making the back of his head look as though his brain has pushed itself to the surface.

The unidentified man first started noticing the condition two years ago, according to a report published this week in the New England Journal of Medicine.

He had looked perfectly normal two years ago, but then his scalp started to morph and began to grow thicker in irregular places, which resulted in bizarre creases of thicker skin across his head in a pattern that was remarkably similar to the shape of a brain.

After doctors ruled out cancer and inflammatory disease, he was diagnosed with cutis verticis gyrate, which is a rare disease that thickens the scalp. Doctors said that there were no other symptoms affecting the young man.

While doctors described the man as "intellectually impaired," they were not able to link his psychiatric or neurological conditions and his poor grades in school to his scalp condition.

Doctors said that the condition is benign and that it only appeared to affect him cosmetically. In fact, the man is reported to be quite happy and proud of his condition.

"The patient did not have the habit of covering his head... The condition did not bother him cosmetically," Dr. Karen Schons a dermatologist at the Hospital Universitario de Santa Maria, who studied the patient said, according to The Sun. "It's a benign and essentially aesthetic condition."

Cutis verticis gyrata was first recorded in 1843 and was first medically classified in 1953. The bizarre condition occurs more commonly in men and usually develops shortly after patients go through puberty.

The cause of the aesthetic deformation is unknown, but it has been associated with brain disorders like schizophrenia and seizures.

Patients with the condition may have between two and ten folds of the skin, which are spongy feeling bumps of skin and creases.

While treatment like surgery can improve the appearance of the scalp, it is expensive and requires regular follow-up treatments. Doctors wrote that a year after the young man was diagnosed, his scalp had looked the same and he continued to have no health or cosmetic concerns.