Intracranial lipomas with teratomatous elements

We report two cases of patients with intracranial tumors that share features with lipomas and teratomas. Although rare reports of lipomas with "hypertrophic nerves" and "teratoid tumors" have been recorded, these two cases are unusual because they contain mature neuroectoderm (choroid plexus, peripheral nerve) and mesoderm (skeletal muscle). The findings are discussed and modern classification schemes are presented. We believe that the cases are examples of a transition between lipoma and teratoma.