Doctors in Beijing reportedly removed a colossal tumor from a man suffering from a condition called neurofibromatosis, according to a report published this week in the U.K.-based online publication The Mirror.

The giant tumor, which weighed 242 lbs. (110 kilograms), started out as a dark birthmark located on the lower back of Yang Jianbin, 37, of Beijing, The Mirror reported.

But is it really possible for a tumor to be that large?

Dr. David Guttman, a professor of neurology at Washington University in St. Louis and director of the university's Neurofibromatosis Center, said that although he has not seen the patient in person, he thinks a tumor of this size is plausible in a patient with neurofibromatosis.

However, tumors the size of Yang's are unusual, Guttman told Live Science in an email. While it is possible for a tumor caused by neurofibromatosis (NF) to grow to such a giant size, Guttman said that in the cases he sees, this rarely happens.

"There is quite a range of tumor sizes in neurofibromatosis one (NF1)," Guttman said, referring to the form of NF that Yang likely has. "This is an exceptionally large tumor, which likely would have been managed differently in most expert NF clinical care centers."

According to The Mirror, the birthmark grew into a fleshy tumor by the time Yang was 9 years old, and it was the size of a fist by the time he was 12. Although Yang previously underwent surgery to remove the tumor, it quickly grew back. [16 Oddest Medical Case Reports]

In people with NF, which is a genetic disorder, cell growth in the nervous system is disturbed, causing tumors to form along nerve tissue.

"We have seen neurofibromatosis patients before," said Dr. Chen Minliang, who led the team of nine doctors that performed the surgery. "But this is the biggest nerve tumor we ever saw," Chen said after the surgery, according to The Mirror.

Guttman said it's likely that Yang has NF1, the more common of the two types of the disorder. However, he noted that he has not treated Yang, and it's difficult to diagnose a person without an examination. According to the National Human Genome Research Institute (NHGRI), NF1 occurs in approximately 1 in 4,000 births, whereas NF2 occurs in only 1 in every 40,000 births.

A symptom called "café-au-lait spots" is one of the most common signs of NF1, according to the NHGRI. Other common symptoms include the appearance of neurofibromas, or pea-size bumps that can grow on the nerve tissue or under the skin, and freckles under the armpits or in the groin area.

The giant tumor removed from Yang's back reportedly took 16 hours to remove, and The Mirror reported that, during the surgery, Yang received about 1.3 gallons (5 liters) of blood.

Yang is reportedly recovering well from his intensive surgery, and could be released from the hospital later this month.

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