Ron Sveden, a retired teacher from Brewster, Massachusetts in the US was astonished to discover that what he thought was a tumor growing in his lung was actually a plant that had sprouted from an inhaled pea.

75-year old Sveden said he was told the pea seed had split and sprouted in his lung. It was about half an inch long (about 1.25 cm), which "is a pretty big thing", he said according to a news report from NBC.

Sveden had been short of breath for several months with emphysema, one of a group of diseases called chronic obstructive pulmonary disease or COPD, when he took a turn for the worse a few months ago in May.

He said he was coughing a lot and feeling listless, so his wife Nancy called 911 and he was rushed to hospital where doctors took X-rays and found that his left lung had collapsed and showing a grainy spot on X-ray.

There followed two more weeks of tests, and Sveden had prepared himself for a diagnosis of lung cancer, but all the tests were negative for cancer. Then one doctor discovered he had a plant growing in his lung, reported NBC.

The doctors told him he must have eaten a pea that "went down the wrong way", and the moist and warm conditions in the lung were just right for it to sprout and grow.

Sveden said he had not felt anything growing in his chest, only that he was coughing a lot.

He underwent surgery to remove the pea, and is now recovering at home.

He said he was very amused when the first meal he had in the hospital after his surgery had peas as the main vegetable. He said he just laughed to himself as he ate them.

His friends have also seen the funny side, they sent him canned peas and pea seeds when he got home.

His wife said:

"God has such a sense of humor. It could have been just nothing, but it had to be a pea, and it had to be sprouting."

Sveden said he doesn't know what might have happened if the pea had gone to full term: he might have ended up working for the Jolly Green Giant, he joked.

" I think the thing that finally dawned on me is that it wasn't the cancer," said Sveden.

Sources: NBC, telegraph.co.uk.

Written by: Catharine Paddock, PhD