Long-term recurrence after surgery for schwannoma of the cauda equina

Abstract

Background: Cauda equina tumors are rare primary spinal tumors. Histologically, the most common tumor arising from the cauda equina is a schwannoma. However, little is known about the long-term postoperative outcomes of cauda equina schwannoma. Here, we reviewed the median-to-long-term postoperative outcomes of eight of our own patients with schwannomas of the cauda equina.

Methods: Between 2007 and 2020, we, retrospectively, reviewed eight patients with cauda equina schwannomas (CESs) undergoing nine operations at our institution. There were five males and three females averaging 56.5 years of age who were followed for over 40 postoperative months. The study included assessment of the following variables: the modified McCormick scale, tumor size, location, extent of resection, treatment of the tumor involving nerve roots, and postoperative observational follow-up.

Results: Gross-total resection was achieved in all eight patients; none received adjuvant therapy. The involved nerve roots were completely sacrificed in seven patients and partially resected in one. During a median follow-up of 108 months, only one patient sustained a tumor recurrence 164 months following the index surgery.

Conclusion: CESs may recur more than 10 years after the original surgery. Radical resection of the tumor, including complete removal of the involved nerve root during the index surgery, and long-term postoperative follow-up is, therefore, essential.

Keywords: Cauda equina schwannoma; Median-to-long-term outcome; Recurrence; Surgery.

Figure 1:

The mid-sagittal view of lumbar MR images before (a and b) and after (c and d) the first surgery. Preoperative T2-weighted (a) and Gd-enhanced T1-weighted (b) images demonstrating intradural cystic tumors at the L2-4 level (white arrowhead). Postoperative T2-weighted (a) and Gd-enhanced T1-weighted (b) images showing no residual tumor.

Figure 2:

The mid-sagittal view of lumbar MR images before (a, b) and after (c, d) the second surgery. T2-weighted (a) and Gd-enhanced T1-weighted (b) images showing tumor recurrence at the levels of L3-4 (white arrowhead). Postoperative T2-weighted (c) and Gd-enhanced T1-weighted (d) images showing the total removal of the recurrent tumor.

Figure 3:

Histopathologic examination of the recurrent tumor. Hematoxylin and eosin-stained sections (a and b) showing spindle cells with myxoid change. Immunohistochemical stains; S-100 (c) and Ki-67 (d).