- The PN must be inoperable, defined as a PN that cannot be surgically completely removed without risk for substantial morbidity due to: encasement of or close proximity to vital structures, invasiveness, or high vascularity of the PN; the PN either causes morbidity or it is growing and has the potential to cause morbidity such as (but not limited to): head and neck lesions that could compromise the airway or great vessels, brachial or lumbar plexus lesions that could cause nerve compression and loss of function, lesions that could result in major deformity (e.g., orbital lesions) or are significantly disfiguring, and lesions of the extremity that cause limb hypertrophy or loss of function or pain; PN growth will be defined as a >= 20% increase in PN volume within approximately 3 years prior to enrollment on this trial