The man manages to live an entirely normal life despite having a brain that is incredibly small for his size. His illness was caused by a fluid buildup in his cranium.

The 44-year-old man’s skull was mostly occupied by a big fluid-filled chamber in the brain called a ventricle, leaving only a thin strip of brain tissue (see an image of the patient’s brain, upper left).

I struggle to pinpoint exactly what proportion of the brain has been diminished because we didn’t use software to measure the brain’s volume.

But optically, it is more than a 50–75% drop, claims Lionel Feuillet, a neurologist at the Mediterranean University in Marseille, France.

Feuillet and his colleagues discuss the case of this patient in The Lancet. He works for the government and is a married father of two.

huge growth

He went to the hospital after feeling a small weakness in his left leg. Feuillet’s staff obtained his medical history and found that when he was a newborn, a shunt was implanted in his head to relieve hydrocephalus, or water on the brain.

The shunt was taken out when he was fourteen. To investigate the condition of his brain, however, the researchers used magnetic resonance imaging (MRI) and computed tomography (CT) scanning. The lateral ventricles, usually tiny chambers containing the cerebrospinal fluid that cushions the brain, were “massively enlarged,” which shocked them.

Although the man had an IQ of 75, which is below the average of 100, this does not necessarily indicate that he is mentally retarded or disabled.

“The whole brain, including the frontal, parietal, temporal, and occipital lobes, was diminished on both the left and right sides. These regions control language, vision, hearing, mobility, and emotional and cognitive functions, according to Feuillet.

The research, in his words, “shows that the brain is quite malleable and may adapt to certain brain damage occurring in the pre- and postnatal period,” if given the proper care.

Max Muenke, an expert in pediatric brain defects at the National Human Genome Research Institute in Bethesda, Maryland, US, says, “What I find surprising to this day is how the brain can deal with something which you think should not be compatible with life.”

“If something happens very slowly over quite a long time, perhaps over decades,” said Muenke, who was not involved in the case, “the other areas of the brain take up functions that would typically be done by the part that is pushed to the side.”