Spontaneous cerebrospinal fluid rhinorrhea associated with an incidental pituitary adenoma

Spontaneous cerebrospinal fluid (CSF) rhinorrhea presenting as the sole symptom of untreated pituitary adenoma is rare, with only 15 cases having been reported in the English literature. All these untreated pituitary adenoma contributing to spontaneous CSF rhinorrhea were diagnosed by the preoperative neuroimaging. Herein, we described an extraordinary rare patient with a pituitary microadenoma, presenting with spontaneous CSF rhinorrhea as the sole symptom. However, this pituitary microadenoma was only found incidentally at surgery, not preoperatively. To the best knowledge of us, this is the first reported case of spontaneous CSF rhinorrhea associated with an untreated pituitary adenoma diagnosed at surgery.