Endodermal cyst with a non- enhancing nodule in the quadrigeminal cistern developed in an octogenarian.

Abstract Background Intracranial endodermal cysts are congenital lesions that generally develop in the cerebellopontine angle and ventral brainstem of the posterior fossa, while endodermal cysts in the quadrigeminal cistern are very rare. We report a rare case of an endodermal cyst in the quadrigeminal cistern with a non-enhancing nodule that developed in patient aged over 80 years. Case Description An 85-year-old man presented to our hospital with progressing gait disturbance and urinary incontinence. Preoperative images showed a cystic mass lesion with a nodule in the quadrigeminal cistern and hydrocephalus. There was no enhanced portion in the lesion, and the intensity of the cyst on magnetic resonance imaging (MRI) revealed a high protein concentration. Subtotal resection was performed due to the adhesion of the cyst to the brainstem. It was diagnosed as an endodermal cyst. The postoperative course was uneventful and hydrocephalus improved. Conclusion This is a rare case of an intracranial endodermal cyst in terms of location and age of onset as compared to previous reports. This case demonstrates that endodermal cysts should be considered as a differential diagnosis for lesions in the quadrigeminal cistern with high protein concentration in the cyst and nodule representing chronic inflammation, regardless of enhancing effects.