Objective: To prospectively evaluate the incidence, risk factors and natural history of postoperative cerebral venous sinus thrombosis (pCVST) in translabyrinthine vestibular schwannoma microsurgical resection and propose a potential management paradigm. Study Design: Prospective, single cohort, multicenter study. Setting: State-wide academic tertiary referral centers. Patients: Fifty-four consecutive patients who underwent translabyrinthine vestibular schwannoma resection. Main Outcome Measures: Incidence of pCVST on postoperative imaging on Day 7, Day 28, and 12 months postoperatively. Patients and tumor characteristics, risk factors, length of stay, intraoperative parameters, complications, and follow-up were analyzed. Results: pCVST was demonstrated in 21 patients (38.9%) on postoperative imaging. All patients with pCVST were treated conservatively and remained asymptomatic in the immediate postoperative period and long-term follow-up. There were no instances of venous infarction, intracranial hemorrhage, or neurological deficits. A majority (61.1%) of pCVST recannalised on long-term follow up with conservative management. There was a statistical association with pCVST and surgery on the side of the non-dominant cerebral venous drainage (n = 17, 80.1%, p = 0.034). Patients with pCVST were significantly more likely to have a postoperative cerebrospinal fluid (CSF) leak (n = 5, 23.8%, p = 0.017). Conclusion: The incidence of pCVST following translabyrinthine vestibular schwannoma resection is much higher than previously recognized. pCVST is more likely to occur when surgery is performed on tumors situated on the side of non-dominant cerebral venous drainage. Despite the high prevalence of this iatrogenic phenomenon, all patients were asymptomatic and a majority resolved, thereby suggesting that conservative management is safe. Correlation between pCVST and increased incidence of CSF leak requires further investigation.

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Background Data relating to the efficacy of immune checkpoint inhibitors (ICI) for salivary gland carcinomas (SGC) is gradually evolving with responses varying among different histotypes. To address these disparities, this retrospective analysis examined the prevalence of recognized biomarkers of response to ICI; namely programmed death‐1 (PD‐1), programmed death‐ligand 1 (PD‐L1), combined positive score (CPS), epidermal growth factor receptor (EGFR), and microsatellite instability (MSI) in patients with SGC with an aim to determine any prognostic or survival benefits and stratify the use of ICI in this disease. Patients and methods Of 52 patients with primary SGC eligible for this study, the most common histological types were adenoid cystic carcinoma (n = 17, 33%), salivary duct carcinoma (n = 14, 27%), mucoepidermoid carcinoma (n = 11, 21%), and acinic cell carcinoma (n = 6, 11%). Immunohistochemistry (IHC) was performed using the Ventana Discovery Ultra auto‐staining platform for EGFR, PD‐1, PD‐L1, and mismatch repair (MMR) proteins. CPS ≥1 defined PD‐L1 positive cases and log‐rank testing was performed to examine the relationship between PD‐L1 expression status and disease‐free survival (DFS) and overall survival (OS). Results CPS positivity was seen in 9 (17.3%) patients, none of which were adenoid cystic carcinoma. All 52 (100%) cases expressed retained MMR proteins inferring microsatellite stability (MSS) and EGFR expression was identified in 45 of 52 (86.5%) patients. CPS positivity (score ≥1) was significantly associated with advanced pathological T status (P = .021), advanced pathological N status (P = .006), high histological tumor grade (P = .045), and positive histological margin (P = .023). Patients with PD‐L1 positivity in tumor cells did not have an inferior 3‐year OS (P = .93). Conclusion The data from this retrospective study highlighting the uniform microsatellite stability alongside the low prevalence of CPS positivity suggests that only a minority of SGC patients may benefit from ICI therapy alone. The high rates of EGFR expression in SGC may be a target to augment immune checkpoint therapy response.