SURGEONS have removed a 13-kilogram “megacolon” from a 22-year-old man.

Shanghai Tenth People’s Hospital said yesterday the operation lasted more than three hours.

The patient, whose huge stomach made him look like a pregnant woman, had complained about a worsening stomach ache for three days. His voice was hoarse and he was moaning in pain. His digestive system and even breathing was overwhelmed, the hospital said.

Yin Lu, the chief doctor in his case, made a preliminary diagnosis of “megacolon” — an abnormal dilation of the colon, the lower part of the bowels where food is transformed to waste, caused by an accumulation of stool.

The doctor’s diagnosis was confirmed by a CT scan.

The patient had suffered from constipation since he was born, the hospital said, and enemas had been used to cleanse his bowels for two decades. His parents had not realized constipation could be a serious medical condition so they hadn’t take him to be examined by a doctor.

Following the surgery, a 76-centimeter-long, 13-kilogram part of his colon was removed. Doctors found it was the lack of a ganglion cell in the colon that had caused the colon’s failure to operate normally.

“Megacolon” is considered a congenital disease. It can be dealt with by surgery, the hospital said.