Background:Pseudomeningocele is the term used to describe fluid accumulation due to the leakage of cerebrospinal fluid into the surrounding soft tissue. It may cause complications such as cosmetic deformities, chronic meningitis, and/or impingement on vital structures resulting in neurological deficits; nevertheless, life-threatening posterior fossa cyst formation is a rare event.Case Description:We report a case of posterior fossa cyst formation induced by pseudomeningocele with brain stem compression leading to coma with pupillary dilation. These symptoms occurred after an operation for left acoustic neuroma. After emergent decompression and dural repair, the patient recovered well without experiencing any further neurological deficits.Conclusion:We discuss the clinical features, possible pathophysiological mechanisms, and treatment options for pseudomeningocele. Although most cases of pseudomeningocele follow a benign course and need only conservative treatment, the potential attendant complications, such as an enlarged cyst, may still have fatal consequences. We believe that it is beneficial to take an aggressive attitude toward this condition and to consider the possibility of surgical interventions more seriously.

Breast cancer metastasis to the conus medullaris is very rare. We report a case of intra-axial conus medullaris metastasis from breast adenocarcinoma in a 39-year-old woman. Two years after the diagnosis of brain metastasis was biopsy-proven, she developed progressive lower limb weakness with urinary incontinence for one month. MRI revealed a contrast-enhancing intramedullary lesion at the conus medullaris. Laminectomy and removal of the tumor were performed for decompression and for preserving function. Postoperative histopathological examinations confirmed the metastatic nature of the lesion. We discuss the possibility of drop metastasis traveling from the brain to the conus medullaris via cerebrospinal fluid (CSF) in the central canal. Since intramedullary spinal cord metastasis can lead to rapid progressive neurological deficits and poor outcome, early diagnosis and decompression could preserve the quality of life. We suggest that CSF cytology could be helpful for the diagnosis of intraspinal metastasis in patients with brain metastasis. Jou rn a l o f Ge ner a l P r a c tic e Drop Metastasis Seeding the Intramedullary Conus Medullaris in a Patient