Prolonged Postoperative Pyrexia and Transient Nonnephrogenic Vasopressin-Analogue-Resistant Polyuria following Endoscopic Transsphenoidal Resection of an Infundibular Epidermoid Cyst

Prolonged postoperative pyrexia (PPP) due to Mollaret’s meningitis following endoscopic transsphenoidal surgery (eTSS) for an intracranial epidermoid cyst can be confused with postoperative meningeal infection after transsphenoidal resection, especially in the middle of the COVID-19 pandemic. Anosmia, as well as dysgeusia, cannot be evaluated in patients of eTSS for a while after surgery. We report a case of an infundibular epidermoid cyst with post-eTSS Mollaret’s meningitis (MM). The post-eTSS MM caused vasopressin-analogue-resistant polyuria (VARP) in synchronization with PPP. A 59-year-old man experiencing recurrent headaches and irregular bitemporal hemianopsia over three months was diagnosed with a suprasellar tumor. The suprasellar tumor was an infundibular cyst from the infundibular recess to the posterior lobe of the pituitary, which was gross-totally resected including the neurohypophysis via an extended eTSS. Since awakening from general anesthesia after the gross total resection (GTR) of the tumor, the patient continuously had suffered from headache until the 13th postoperative day (POD13). The patient took analgesics once a day before the surgery and three times a day after the surgery until POD11. Pyrexia (37.5–39.5 degree Celsius) in synchronization with nonnephrogenic VARP remitted on POD18. Intravenous antibiotics had little effect on changes of pyrexia. Serum procalcitonin values (reference range