A One-Sided Argument

Question:  A 36 year old male is referred to you for nasal polyps.  Examination reveals exclusively left sided nasal polyposis originating from the nasal septum.  The patient had undergone empiric treatment with nasal steroids without benefit.  What is your presumptive diagnosis and next step in management?  [Answer will be posted with next week's new question]

Answer to last week's question, "Name What Inflames" (June 27, 2016): 

IgG4 related disease.