A 'white patch' is too undefined a description to permit a logical comment! This could be anything from an inflammatory area to atelectasis
(an area of non-aerated lung) If atelectatic, then a bronchial obstructing lesion is possible although no mention was made of any volume loss. Bronchoscopy
could find and remove a foreign body or take a sample if it is judged to be a localized infection.
R. Lund, M.D.