A package of marijuana has been retrieved from the nose of a man 18 years after he smuggled it into prison, in what doctors have described as the first case of its kind.

According to the team who reported on the case in the British Medical Journal, the man received the drugs wrapped in a balloon from his girlfriend who was visiting him in prison.

He placed the drugs in his right nostril in order to evade detection from guards, but was later unable to retrieve them after pushing the package deeper into the cavity.

Despite suffering chronic sinus infections and symptoms of nasal obstructions in the years following the incident, the man mistakenly believed he had ingested the drugs.

Over the next 18 years, the package developed into a rhinolith — a stone that forms around a foreign body in the nasal cavity through the slow deposition of calcium and magnesium salts.

Titled “A nose out of joint,” the report by doctors at Westmead Hospital in Sydney, Australia, said that the man only learned the truth of his sinus discomfort after seeking medical attention for what he believed was a totally unrelated issue.

“A 48-year-old man was referred to the Westmead ENT Department after a CT of the brain, originally performed for headaches, demonstrated an incidental 19x11mm calcified lesion in the right nasal cavity,” the report states.

“On questioning, the patient confirmed a long history of unilateral right nasal obstruction and recurrent sinonasal infections.”

The rhinolith was removed from the man’s nose under general anesthetic, and a subsequent study revealed that it contained a “rubber capsule containing degenerate vegetable/plant matter.”

“On follow-up and specific questioning, the patient was able to recall an incident that occurred 18 years prior, while he was incarcerated,” the report states. “He remained unaware of the package’s presence until presented with the unusual histopathology report.”

Three months following the removal of the unexpected foreign body, the man reported that his nasal discomfort had completely resolved.

The researchers believe that this is the first reported case of a “prison-acquired marijuana-based rhinolith.”

They noted that the majority of drug smuggling in prisons occurs through ingesting packages through the mouth, which are later retrieved after being passed through the gastrointestinal tract. Inserting drugs into the nasal cavity for the purposes of avoiding detection is “relatively rare,” they added.

Rhinoliths can form around a wide variety of foreign objects, such as beads or seeds, and around bodily matter, including dislodged teeth or blood clots.

They are relatively rare, accounting for around one in every 10,000 ear, nose and throat outpatient visits, according to the study.

Patients suffering from the concretions typically present with a variety of symptoms, including nasal obstruction, headaches, facial pain and discharge from the nose.