The 16-year-old, from New York, complained to doctors he had 'sweaty nipples and they diagnosed hima brain tumour. It turned out the 'sweat' was actually breast milk. The boy also had narcolepsy, headaches and falls, The Daily Mail reports.

Neurologist Sandra Block, treating the boy, explained this is caused by the  production of the wrong hormones and formation of lactation glands in the body. It happens with an active pituitary adenoma, a benign tumor in the middle of the brain.

As a result of it the boy also continually exhausted - falling asleep anywhere and everywhere, including while playing the trumpet and at a heavy metal concert.

The boy's name is not disclosed, he is only known as Duncan.

At first doctors were sure he had narcolepsy with cataplexy. The latter is an episode of muscular weakness triggered by strong emotions such as laughter, anger and surprise.

They were ready to pronounce the diagnosis, when Dincan showed them his 'sweaty nipples', turning red.

Having reconsidered their options after the plot twist, they discovered the true cause, that is a benign brain tumour.

His haywire hormones were causing him to produce milk - a condition called galactorrhea.

The diagnosis was confirmed by an MRI and the tumour was removed successfully, relieving Duncan of his symptoms.