Introduction: Ectopic pituitary adenomas (EPAs) are uncommon tumors originating outside the sella turcica, posing diagnostic challenges due to varied presentations. We report the third documented case of an EPA arising from the third ventricle floor (3VF), who was successfully treated surgically. Case presentation: A 70-year-old male presented with visual impairment. Visual field tests addressed compressive optic neuropathy. Imaging revealed a well-defined mass arising from 3VF compressing the optic chiasm, confirmed as a nonfunctional EPA through histopathological and hormonal analyses. The patient underwent a lateral subfrontal translamina terminalis approach for tumor resection, ensuring maximal preservation of adjacent neurovascular structures. The procedure involved meticulous debulking of the tumor, careful preservation of the optic chiasm and hypothalamus, and watertight dural closure to minimize postoperative complications. Surgical intervention resulted in complete tumor resection without complications, leading to improved visual and endocrine function postoperatively. Conclusions: This technique emphasized minimal brain manipulation and optimal preservation of neural integrity, contributing to the patient’s successful recovery following surgery. This surgical technique can be applied in similar 3VF cases, ensuring successful outcomes with minimal complications.