Clinical Features and Surgical Management for Spinal Plexiform Schwannomas: Three Case Series and Literature Review

Plexiform schwannomas that arise in a single cauda equina are extremely rare among spinal cord tumors.We reviewed all operative records of spine surgeries performed at a single institute over 18 years and identified three cases of plexiform schwannoma amongst 113 intradural extramedullary (IDEM) tumors (2.7%).The average age of the patients was 70 years old (range 68-73), and two were male.The tumors were located in the thoracolumbar region (T11-L2) and were associated with symptoms such as lower limb weakness, sensory deficits, and urinary dysfunction, suggesting epiconus or conus syndrome.All three cases involved tumors resembling a "string of beads" along a single cauda equina.Magnetic resonance (MR) imaging showed typical schwannoma features in large nodules, such as the "target sign," but small nodules exhibited complete enhancement without the "target sign."Tumor resection was successfully performed under multilevel laminectomy; however, postoperative thoracolumbar kyphosis occurred in one case.Histopathological examination confirmed the tumors as schwannomas with no malignant findings.In all three cases, symptoms were alleviated and there was no impairment in daily life.There was also no recurrence, confirmed by MR imaging at the postoperative follow-up.The imaging characteristics of plexiform schwannomas can mimic malignant tumors, including drop and leptomeningeal metastases, due to their heterogeneous morphology and signals on MR images.If malignancy is suspected, additional examinations, such as positron emission tomography and cerebrospinal fluid biopsies, should be recommended.