Various conditions can cause myelopathy due to cervical epidural fluid collection, including idiopathic cervical epidural hematoma, traumatic cervical epidural hematoma, infectious myelitis, epidural abscess, spinal cord infarction, post-traumatic cerebrospinal fluid (CSF) leakage, and epidural tumors. While physical compression from hematoma, abscess, or epidural tumors is common, and carcinomatous meningitis can cause CSF flow obstruction and accumulation leading to myelopathy, rapid progression of serous fluid collection causing myelopathy is rare. We report a case of myelopathy caused by rapid accumulation of epidural exudate from a metastatic tumor in the cervical lamina. A 59-year-old male with a history of lung cancer with metastasis to the C3 lamina, who was previously independent in activities of daily living, presented to the emergency department with progressive quadriparesis and urinary dysfunction after farming work. An acute cervical epidural hematoma was initially diagnosed, and emergency surgery was subsequently performed. Intraoperatively, no clear epidural hematoma was found, but serous, light yellow, clear fluid collection was observed in the epidural space. After drainage and partial C3, C6 laminectomy and complete C4, C5 laminectomy for decompression, neurological symptoms improved significantly. Postoperative spinal myelography showed no evident CSF leakage into the cervical epidural space. However, on postoperative day 20, bilateral lower limb weakness recurred with more fluid accumulation than preoperatively. During reoperation, exudate was observed from the remaining portion of the C3 lamina with known lung cancer metastasis. Believing the spinal cord compression from this fluid collection to be the cause of myelopathy, the metastatic C3 lamina was completely removed to prevent recurrence. No obvious dural fistula was observed. After reoperation, no significant epidural fluid collection causing spinal cord compression was observed, and the patient was discharged home with a modified Rankin scale score of 4.