Nontraumatic intradiploic pseudomeningoceles and de novo syringomyelia formation are very rare entities. The authors have previously reported the case of a 4-year-old girl who underwent foramen magnum decompression without dural closure for Chiari I malformation. Three years after the operation an intradiploic pseudomeningocele was documented, but the patient was lost to follow-up without undergoing revision surgery. Four years later, at the age of 11 years, the patient returned for treatment of intensifying symptoms. Radiological imaging then showed an increase in the size of the intradiploic pseudomeningocele and a new cervical syrinx. The patient underwent a first revision surgery in which a part of the internal layer of the occipital bone was removed and arachnoid scar lysis was performed. Two months later the syrinx had worsened, and in a second revision surgery a pseudomeningocele-peritoneal shunt was placed. Here, the authors describe what is to their knowledge the first case of an intradiploic pseudomeningocele and de novo syringomyelia formation following Chiari I decompressive surgery.
Arthur R. Kurzbuch, Benedict Rilliet, Maria-Isabel Vargas, Colette Boex and Enrico Tessitore
The authors report the case of a 58-year-old man presenting with a 3-year history of clinical signs of progressive cervical spondylotic myelopathy (CSM). Magnetic resonance imaging showed a severe stenosis of the cervical spinal canal at C3–4 and C5–6 levels due to multiple discopathies. High signal intensities on T2-weighted MR images of the spinal cord and low signal intensities on T1-weighted images at the C2–6 levels were noted, as was contrast enhancement at the C3–4 level. The patient underwent a bilateral decompressive laminectomy at C3–6. The patient did not show any clinical improvement. Thus, further cervical MR imaging was performed and the differential diagnosis of an intramedullary tumor was considered in view of the persisting intramedullary enhancement. This diagnosis prompted a second operation involving a posterior midline myelotomy and excision of an intramedullary ependymoma at the C3–4 level. Intramedullary tumors should be considered in the differential diagnosis of CSM with an atypical pattern of MR imaging features.