tornwaldt cyst tornwaldt cyst a tornwaldt cyst also spelt as thornwaldt or thornwald cyst is a benign cyst located in the upper posterior nasopharynx. it can be seen on computed tomography (ct) or magnetic resonance imaging (mri) of the head as a well-circumscribed round mass lying in the midline. in most cases, treatment is not necessary. it was first described by gustav ludwig tornwaldt. tornwaldt cysttornwaldt cyst imaged on sagittal mri (flair). the cyst appears hyperintense in the midline of the nasopharynx (arrow). in this case there is also a cyst of the pinealis gland (arrowhead) showing a signal intensity slightly higher than the csf.specialtyent surgery