Case Report |
Corresponding author: Polina Angelova ( dr.polina.angelova@gmail.com ) © 2024 Ivo Kehayov, Atanas Davarski, Polina Angelova, Borislav Kitov.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Kehayov I, Davarski A, Angelova P, Kitov B (2024) Sacral nerve root metastasis in a patient with lung carcinoma resembling neurinoma – a case report and literature review. Folia Medica 66(1): 136-141. https://doi.org/10.3897/folmed.66.e111619
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Intradural extramedullary metastases from systemic neoplasms are very rare, with an incidence ranging from 2% to 5% of all secondary spinal diseases. We present the case of a 53-year-old man diagnosed with lung adenocarcinoma with symptoms of severe back pain and tibial paresis. The magnetic resonance imaging (MRI) revealed an intradural lesion originating from the right S1 nerve root mimicking neurinoma. Total tumor removal was achieved via posterior midline approach. The histological examination was consistent with lung carcinoma metastasis. Due to the rarity of single nodular nerve root metastases, MRI images may be misinterpreted as nerve sheath tumors, such as schwannomas or neurofibromas. We performed a brief literature review outlining the mainstay of diagnosis, therapeutic approach, and the prognosis of these rare lesions.
intradural, leptomeningeal metastasis, MRI, nerve root, spine, surgery
With an incidence ranging from 2% to 5% of all secondary spinal illnesses, intradural extramedullary metastases (IEM) from systemic neoplasms are extremely uncommon. They can be either solitary or multiple.[
IEM are observed in cases of malignant cell dissemination into the cerebrospinal fluid through the leptomeninges. Although the evidence for IEMs is limited to a few case reports or small case series, they are considered to be predominantly epithelial in origin. The primary sources are most commonly breast carcinoma (12%–35%), lung carcinoma (10%–26%), and gastrointestinal tract carcinoma (4%–14%).[
In addition to providing a brief literature analysis of cases of nerve root metastasis that have been published, the current research aims to present the case of a patient with lung cancer who had both nodular nerve root metastasis and intracerebral and leptomeningeal spinal metastases (LSM).
We present the case of a 53-year-old male patient with histologically verified lung adenocarcinoma who underwent chemotherapy and radiation therapy. Six months later, he presented with onset of severe back pain that radiated toward the posterior surface of the right leg followed by acute weakness of plantar flexion of the right foot. The neurological examination on admission to hospital revealed severe back pain (VAS 10/10), radicular hyperalgesia (VAS 10/10), and hyperesthesia along the right S1 dermatome. He also had tibial nerve plegia of the right foot, muscle weakness measured 0/5 with inability for plantar flexion. Noncontrast magnetic resonance imaging (MRI) revealed an intradural extramedullary tumor at the S1 level, originating from the nerve root, which was initially interpreted as neurinoma (Figs
The patient was operated on via typical midline posterior surgical access. The right S1 nerve root was found to be thickened. Meticulous dissection between the root fibers was performed (Fig.
During the postoperative period, the radiculopathy was partially resolved. The weakness of the right foot persisted but the pain was gradually reduced to 2/10 according to VAS. On the second postoperative day, the patient reported headache and loss of vision in both eyes and left eyelid drop. A new set of neurological symptoms that pointed to cerebral involvement prompted us to perform a contrast-enhanced MRI of the brain and spine axis. It revealed multiple intracerebral metastases, including several lesions located in the optic nerve and optic chiasm, as well as other multiple intradural “drop” metastases in the cervical and lumbar spinal segments (Figs
Pre-operative T2-weighted MRI demonstrating an isointense intradural tumor mass in the right S1 nerve root on sagittal, axial, and coronal projections (arrows); (D-F): Intraoperative images illustrating important steps of the microsurgical tumor removal. Tu: tumor; S1: first sacral nerve root; S2: second sacral nerve root
Histological examination verifying undifferentiated small cell neuroendocrine lung carcinoma (Hematoxylin-Eosin staining, ×100).
Postoperative contrast-enhanced brain and spine MRI: А. Sagittal Т1-weighted cervical MRI demonstrating intradural extramedullary metastases at С4–С5, С8, and Th1 levels (arrows); B, C. Sagittal and axial T1-weighted lumbar MRI visualize intense contrast enhanced nodule at the level of L4 vertebrae (arrows).
We present a concise review of nerve root metastases reported in the literature and initial clinical symptoms (Table
Brief overview of published cases with lumbo-sacral nerve root metastasis.[
Author | Primary Source | Affected nerve root | Symptoms |
Johnson et al.[ |
Colonic adenocarcinoma | N/A | No symptoms |
Johnson et al.[ |
Lung carcinoma | N/A | Foot drop |
Wigfield et al.[ |
Colonic adenocarcinoma | L1 | Pain syndrome |
Uchida et al.[ |
Uterine adenocarcinoma | S1 and S2 | Low back pain; radicular pain and numbness |
Schulz et al.[ |
Breast carcinoma | L2 | Radicular pain |
Mitchell et al.[ |
Ewing sarcoma | L4 | Low back pain; radicular pain and numbness |
Ito et al.[ |
Breast carcinoma | S1 | Low back pain; leg muscle weakness |
Cabrilo et al.[ |
Renal cell carcinoma | L5 | Low back pain; radicular pain and numbness |
Slotty et al.[ |
Lung adenocarcinoma | L3 | Radicular pain and numbness |
Strong et al.[ |
Renal cell carcinoma | L4 | Radicular pain and numbness |
Li et al.[ |
Squamous cell carcinoma | L5/S1 | Radicular pain |
Oktay et al.[ |
Lung adenocarcinoma | S1 | Low back pain; leg muscle weakness, numbness, and hyperalgesia |
Di Sibio et al.[ |
Gastric adenocarcinoma | S1 | Low back pain; radicular pain and numbness |
Zhang et al.[ |
Breast carcinoma | S1 | Radicular pain |
Zhang et al.[ |
Breast carcinoma | L5 and bilateral cervical roots | Radicular pain and numbness |
Norouzi et al.[ |
Breast carcinoma | S1 | Radicular pain |
Our case | Lung neuroendocrine carcinoma | S1 | Low back pain; radicular pain; acute tibial nerve plegia |
Lung carcinoma is the most common malignant disease, accounting for approximately 34% of all male and 22% of all female cancer deaths and most commonly metastasizes in the central nervous system (20-25%), the cervical lymph nodes (15-60%), bones (25%), and the liver (10-15%).[
The possible routes for cancer cell dissemination to the nerve roots are arterial, venous or lymphatic spread, local invasion through the dura, and dissemination via the cerebrospinal fluid (CSF) into the subarachnoid space, so-called “drop metastases” or LSM.[
The clinical presentation of LSM includes cauda equina syndrome, communicating hydrocephalus, and cranial neuropathies. Early in the course of the disease, neurological symptoms can be minimal, such as radiculopathy or visual disturbances. As mentioned, we also observed damage to second and third cranial nerves in addition to S1 nerve root.[
There are two types of LSM distribution – diffuse and nodular. The diffuse type is characterized with free floating non-adherent cancer cells, while the nodular consists of leptomeningeal tumors that tend to enhance with gadolinium on MRI.[
While diffuse LSM can remain asymptomatic, nodular spinal metastases usually cause nerve root compression, resulting in radicular pain, radiculopathy, or cauda equina syndrome.[
LSM can occur at all spinal levels. According to Carminucci and Hanft, and Mariniello et al., LSM are rare in the area of the cauda equina, while Palmisciano et al. report that in this area they are most common, which is explained by the slow circulation of cerebrospinal fluid.[
The presented case is an example of the development of early metastatic lesions (in less than 1 year) after applying multidisciplinary treatment with radiation and chemotherapy. This fact could be explained by the loss of receptors, susceptible to chemotherapeutic drugs, and progression of the most sustainable and undifferentiated tumor cells.[
Most authors recommend surgical decompression and partial or total metastasis removal in patients with acute motor deficit or cauda equina syndrome.[
The presence of multiple intracerebral metastases and LSM requires an assessment of the risk of possible postoperative complications. We hypothesize that in our case, the ocular symptoms that developed on the second postoperative day may have resulted from the excessive CSF drainage during the intradural part of the surgery, which led to acute compression of the optic and oculomotor nerves by cerebral metastasis.
LSM are late complications of systemic cancer that significantly worsen the quality of life of patients and are associated with high mortality. When an intradural extramedullary tumor is detected in the region of the cauda equina in a patient with previously diagnosed systemic cancer, possible metastasis should be included in the differential diagnosis. In these cases, a contrast-enhanced MRI of the brain and spine axis should be performed to establish or exclude the presence of parenchymal and/or LSM. The risk of complications following palliative surgical intervention should be carefully assessed for each individual case.
Conception or design of the study: B.K.; data collection: P.A.; data analysis and interpretation: I.K.; drafting the manuscript: B.K.; critical revision of the manuscript: I.K.; other (study supervision, fundings, materials, etc.): P.A.; final approval of the version to be published: I.K.
Informed consent was obtained from all individual participants included in this study.
There is no conflict of interest to disclose.
None