Multiple neuroenteric cysts at cerebello-pontine angle and foramen magnum: a case report and review of the literature.

Neuroenteric cysts of the CNS are uncommon benign lesions usually involving the spinal cord or rarely the cerebellopontine angle (CPA). We report a rare example of multiple neuroenteric cysts arising from the CPA and foramen magnum in a 20-year-old Caucasian woman who presented with headaches and dizziness. An MRI showed three separate lesions, not communicating with each other. The first lesion, within the left posterior lateral aspect of the CPA, demonstrated isointensity to gray matter on the fluid-attenuated inversion recovery (FLAIR) sequence. The second lesion, within the left foramen of Luschka at the level of the CPA, demonstrated hyperintensity on the T-2-weighted sequences, intermediate to slightly hyperintense on T-1-weighted sequence and hyperintensity on FLAIR. The third lesion, within the anterior/inferior left cerebellum at the level of the foramen magnum, followed CSF signal intensity throughout. None of the lesions demonstrated significant enhancement or bone lesions. Due to compression effect, surgery was performed. Pathologic examination revealed cystic structures lined by a single layer of non-ciliated well-differentiated mucin-producing columnar epithelium with eosinophilic to amphophilic cytoplasm and round to oval nuclei with focal pseudostratification. Immunohistochemical studies showed focal positivity for cytokeratin 7, CK 5/6, synaptophysin, and carcinoembryonic antigen (CEA), diffuse positive staining for epithelial membrane antigen (EMA) and BerEP4; and negative staining for cytokeratin 20, TTF-1, and GFAP. The MIB-1 proliferation index was < 1%. One-year follow-up has shown no recurrence. The differential diagnosis and a brief review of the literature are also presented.