How common are symptomatic adenoids causing otitis media witheffusionin adult patients. ?

This 39 year gentleman presented with recurrent right side otitis media with effusion. Nasal endoscopy showed a mass in Nasopharynx blocking right side Eustachian tube. A MRI was done which suggested it to be Adenoids.a biopsy was also done which showed it to be reactive hyperplasia of lymphoid tissue.  

Right side Grommet was put.