Fully Endoscopic Retrosigmoid Approach For Pontine Metastasis As An Initial Presentation Of Lung Cancer: Surgical Anatomy And A Technical Case Report

The standard microsurgical retrosigmoid approach (mRSA) is one of the most commonly used techniques to access pontine lesions, and in recent years it has been enriched with the introduction of endoscopic methods. Although endoscopic retrosigmoid approaches (eRSAs) have been increasingly applied to various posterior fossa lesions, surgical treatment of a pontine metastasis using this technique has not been previously reported. We present the case of a previously healthy 72-year-old man who developed progressive right hemiparesis and gait disturbance. Magnetic resonance imaging revealed a cystic mass in the left side of the pons. Due to worsening symptoms, the patient underwent a fully endoscopic retrosigmoid approach with intraoperative neurophysiological monitoring, utilizing the peritrigeminal safe entry zone. Postoperatively, neurological function improved, and histopathological examination confirmed metastatic small cell carcinoma. To our knowledge, this is the first report of successful utilization of a fully endoscopic retrosigmoid approach in the management of a metastatic pontine tumor, emphasizing the surgical anatomy, technical nuances, and the importance of further case collections and collaborative studies to clarify the role of this minimally invasive approach.