Paraneoplastic stiff-person syndrome in a girl with a petrous bone chondrosarcoma

Stiff-person syndrome (stiff-man syndrome) is characterized by hyperxcitability of voluntary muscle and progressive spasticity. We report on an 18 year old woman who was treated orthopedically for mild spasticity after premature birth. At the age of 12 years her muscular tone increased rapidly with associated pyramidal tract signs. Soon cycling and independant walking became impossible. The process which started at the legs spread through the arms to the face. The patient became bedridden and care became difficult. The speech was slowed and breathing took higher efforts. Radiologic, electrophysiologic and laboratory examinations including neurotransmitters and antineural antibodies could not explain the clinical picture. The only pathological finding was an enhancing tumor located in the right petrous bone. Biopsy revealed a chondrosarcoma WHO II°. No further localizations of the tumor could be detected on a whole-body PET scan. This kind of sarcoma very rarely is associated with paraneoplastic symptoms. As the location of the tumor prevented a total resection and multiple medical trials incuding intrathecal baclofen and high dose steroids were not able to reduce the muscular tone a stereotactic photon therapy was initiated. A reduction of tone could already be seen during the therapy and the muscles continued to relax for several weeks so that the girl became able to walk and care for herself again. Unfortunately the muscular tone increased slowly again after 2 years of stability and she lost her ability to walk again. Despite a specific molecule could not be found causing the described clinical picture which resembles stiff-person syndrome, a paraneoplastic process is most likely in view of the positive effect of the local radiotherapy. A whole body investigation to find a causative tumor seems appropriate if such a specific and marked clinical syndrome could not be explained by other (laboratory) findings.