The Interest Group Acoustic Neuroma (IGAN) is a free, non-organized self-help group in the form of a «loose association», i.e. without any legal form, statutes, a formal declaration of membership, or indeed a membership fee. IGAN brings together people and institutions across national borders who have one common problem – namely an acoustic neuroma brain tumor – and who give their time voluntarily because they want to work together to «help people to help themselves» to find solutions to this problem.