2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Diseases Of The Nervous System And Sense Organs 320-389 > Diseases Of The Ear And Mastoid Process 380-389 > Mastoiditis And Related Conditions 383.* > 2006 ICD-9-CM Diagnosis 383.31 Mucosal cyst of postmastoidectomy cavity View the most recent version of ICD-9-CM 383.31 383.31 is a specific code that can be used to specify a diagnosis 383.31 contains 2 index entries View the ICD-9-CM Volume 1 383.* hierarchy  Index entries containing 383.31: Complications surgical procedures 998.9 postmastoidectomy 383.30 cyst, mucosal 383.31 Cyst (mucus) (retention) (serous) (simple) postmastoidectomy cavity 383.31