Doctors have told of their surprise after discovering a Portuguese woman they were examining had two anal canals.

The unidentified patient was referred to specialists after enduring two abscesses on her bottom, which both required 'drainage'.

Upon closer inspection, medics in Figueria da Foz - 87 miles (140km) south of Porto, saw two holes leaving her anus - instead of the usual one.

The 40-year-old woman refused numerous offers of surgery to correct her defect, which medics say she would have been born with.

Proctologists - specialists in anal health - were so intrigued by the bizarre case that they decided to publish it in a medical journal.

The unidentified patient was referred to specialists after enduring two abscesses on her bottom, which both required 'drainage' (pictured, an MRI scan showing a tubular structure posterior to the anal canal, pointed to by an arrow)

Writing in the Journal of Medical Cases, they revealed anal canal duplication is 'the most uncommon' malformation of the digestive tract.

They wrote: 'This case is of particular importance because of its rarity. Around 60 cases of ACD are currently described worldwide.

'Our patient was diagnosed at the age of 40 years, constituting one of the most elderly patient diagnosed with ACD.'

They revealed that 'diagnosis is usually made in the first year of life by caregivers', stressing it is unusual for it to be discovered in adults.

Upon closer inspection, medics in Figueria da Foz - 87 miles (140km) south of Porto, saw two holes leaving her anus (scans confirmed it was a duplication of the anal canal)

The 40-year-old woman refused numerous offers of surgery to correct her defect, which medics say she would have been born with (arrow points to the orifice)

WHAT IS THE ANAL CANAL? Faecal matter passes through the anal canal, which connects directly to the rectum - where waste is stored before it leaves the body. The tube, which is roughly 4cm-long, is the last part of the gastrointestinal tract. Medical literature states around 60 cases of anal canal duplication have been recorded across the world. Humans are meant to be born with just one canal, and a duplication is deemed to be the 'mots uncommon' malformation of the digestive tract. If the duplication connects to the rectum, then, in theory, the patient would be able to pass waste through both orifices. Advertisement

Faecal matter passes through the anal canal, which connects directly to the rectum - where waste is stored before it leaves the body.

In theory, the woman could have been able to excrete through both, if her second canal linked to the rectal wall, which it didn't.

Instead, doctors revealed the 'tubular and cul-de-sac' shaped orifice, separated from the other canal by just skin, was just 3cm deep and 1cm wide.

Hospital Distrital da Figueira da Foz explained how the woman came to them after she reported two anal abscesses that needed surgically draining in the past year.

She was referred for a consultation with proctologists, led by Dr Jessica Neves - despite no longer having any painful pus-filled lumps.

Examination revealed the two orifices, and medical scans to help doctors identify the problem confirmed it was a duplication of the anal canal.

Doctors asked the patient if she wished to undergo surgery to correct her defect at the time, but she refused.

Seven years later she returned to the same clinic complaining of a new abscess on her bottom and was again offered surgery. However, she again declined.