Heterotopic glioneuronal mass of the cerebellomedullary cistern with duct cyst formation of ectopic salivary gland tissue.

We report the unique presentation of a glioneuronal heterotopia in the cerebellomedullary cistern in association with salivary gland and adipose tissue in a 56-year-old woman. The patient presented with persistent pain of the posterior neck and was diagnosed with a snow-man shaped cystic solid mass in the cerebellomedullary cistern of the posterior fossa on brain MRI. Surgical exploration revealed a tan to gray solid mass with a cystic portion that was ruptured during surgery. Histologically, the mass consisted of glioneuronal cells in the gliofibrillary or neuropil matrix and was diagnosed as glioneuronal heterotopia. This heterotopic glioneuronal mass contained CD34-positive neuroglial cells and pericellular stroma. In addition, an island of normal-appearing salivary gland and adipose tissue was found in close relationship with the mass. The cystic portion of the mass was a duct cyst of the salivary gland. The pathogenesis of this case with heterotopic glioneuronal, salivary and adipose tissues remains unclear.