A case of heterochromia iridis and Horner's syndrome is reported in a 7-year old 
girl with paravertebral neurilemmoma. These clinical findings can be useful in 
the early diagnosis of mediastinal tumors in the paravertebral axis. While 
typically associated with neuroblastoma, these findings can be due to tumors 
which are inately benign--in this case neurilemmoma. The mechanism for 
heterochromia is briefly discussed.