Voluminous free disk fragment mimicking an extradural tumor

Differential Diagnosis of Mimicking Tumor Discs Using Coronal Magnetic Resonance Imaging of Three-Dimensional Fast-Field Echo with Water-Selective Excitation: A Single Center Retrospective Study

OBJECTIVE

As disc fragment completely loses contact with the parent disc and can migrate in all directions of the epidural space, making it appear similar to schwannoma, it is fairly difficult to make a definitive diagnosis for mimicking tumor discs. The aim of this research is to differentially diagnose mimicking tumor discs and schwannomas using coronal magnetic resonance imaging (MRI) of three-dimensional fast-field echo with water-selective excitation (CMRI).

METHODS

Among 76 patients (38 men and 38 women; mean age, 52.88 ± 15.80 [range, 18-78 years]) who were retrospectively examined in this study, 38 were primarily diagnosed with schwannomas and pathologically diagnosed with mimicking tumor discs after surgery, and 38 were primarily diagnosed with neurogenic tumors and pathologically diagnosed with schwannomas after surgery. Open surgery was performed in all the patients between March 2016 and April 2020. The preliminary diagnosis of all patients was considered an intraspinal tumor based on conventional two-dimensional MRI sequences. After open surgery, the final diagnosis was confirmed to mimic a tumor disc or schwannoma based on postoperative pathology reports. The sensitivity, specificity, and reliability of CMRI and conventional MRI for identifying mimicking tumor discs and schwannomas were compared. Chi-square and McNemar tests were used for statistical analyses.

RESULTS

Symptoms were considerably relieved in all the patients after surgery. Seven patients had grade 1 extensor digitorum longus, triceps surae, or quadriceps femoris muscle strength prior to surgery. No nerve root injury was observed in any of the patients. CMRI showed significantly higher sensitivity (94.74%) and specificity (94.74%) than conventional MRI (71.05% and 92.11%, respectively; p = 0.012 < 0.05, and p = 1 > 0.05, respectively) for differential identification between mimicking tumor discs and schwannomas. Moreover, CMRI showed a higher reliability (kappa value = 0.787) than conventional MRI (kappa value = 0.374).

CONCLUSIONS

CMRI is a better non-invasive technology for the identification of intraspinal lesions, especially for differentiating between mimicking tumor discs and schwannomas.

Lumbar disc sequestration mimicking a tumor: Report of four cases and a literature review

BACKGROUND

Disc herniation refers to the displacement of disc material beyond its anatomical space. Disc sequestration is defined as migration of the herniated disc fragment into the epidural space, completely separating it from the parent disc. The fragment can move in upward, inferior, and lateral directions, which often causes low back pain and discomfort, abnormal sensation, and movement of lower limbs. The free disc fragments detached from the parent disc often mimic spinal tumors. Tumor like lumbar disc herniation can cause clinical symptoms similar to spinal tumors, such as lumbar soreness, pain, numbness and weakness of lower limbs, radiation pain of lower limbs, etc. It is usually necessary to diagnose the disease according to the doctor's clinical experience, and make preliminary diagnosis and differential diagnosis with the help of magnetic resonance imaging (MRI) and contrast-enhanced MRI. However, pathological examination is the gold standard that distinguishes tumoral from non-tumoral status. We report four cases of disc herniation mimicking a tumor, and all the pathological results were intervertebral disc tissue.

CASE SUMMARY

The first case was a 71-year-old man with low back pain accompanied by left lower extremity radiating pain for 1 year, with exacerbation over the last 2 wk. After admission, MRI revealed a circular T2-hypointense lesion in the spinal canal of the L4 vertebral segment, with enhancement on contrast-enhanced MRI suggesting neurilemmoma. The second case was a 74-year-old man with pain in both knees associated with movement limitation for 3 years, with exacerbation over the last 3 mo. MRI revealed an oval T2-hyperintense lesion in the spinal canal at the L4–5 level, with obvious peripheral enhancement on contrast-enhanced MRI. Thus, neurilemmoma was suspected. The third case was a 53-year-old man who presented with numbness and weakness of the lumbar spine and right lower extremity for 2 wk. MRI revealed a round T2-hyperintense lesion in the spinal canal at the L4–5 level, with obvious rim enhancement on contrast-enhanced MRI. Thus, a spinal tumor was suspected. The fourth case was a 75-year-old man with right lower extremity pain for 2 wk, with exacerbation over the last week. MRI revealed a round T1-isointense lesion in the spinal canal of the L3 vertebral segment and a T2-hyperintense signal from the lesion. There was no obvious enhancement on contrast-enhanced MRI, so a spinal tumor was suspected. All four patients underwent surgery and recovered to ASIA grade E on postoperative days 5, 8, 8, and 6, respectively. All patients had an uneventful postoperative course and fully recovered within 3 mo.

CONCLUSION

Disc herniation mimicking a tumor is a relatively rare clinical entity and can be easily misdiagnosed as a spinal tumor. Examinations and tests should be improved preoperatively. Patients should undergo comprehensive preoperative evaluations, and the lesions should be removed surgically and confirmed by pathological diagnosis.

Two cases in which 3D MRI was used to differentiate between a disc mass that mimics a tumor and neurinoma

Background

Since disc sequestration that mimics a tumor is rare and sometimes presents with an atypical appearance upon magnetic resonance imaging (MRI), it is often confused with other more common epidural and intradural neoplasms, particularly neurinoma. Open surgery is necessary due to the difficult of achieving a definitive diagnosis using computed tomography, MRI, and gadolinium- enhanced MRI prior to operation. Herein, we describe the use of coronal MR images of 3D fast-field echo with water selective excitation in the diagnosis of disc sequestration mimicking a tumor.

Case presentation

Two patients were admitted to our hospital with back pain, radiating pain, and hypoesthesia in the right lower limb. MRI revealed tumor-like masses in the lateral recess of L3 and posterior to the body of L4. The initial diagnosis indicated disc sequestration mimicking a tumor and neurinoma. The coronal MR images of 3D fast-field echo with water selective excitation showed a clear boundary between the tumor-like mass and the nerve root. Moreover, the mass was also completely separated from the dura. Therefore, neurinoma was excluded as a possible diagnosis prior to operation. Surgical excision to perform removal of the gross mass was performed in one patient. The histopathological diagnosis was consistent with the 3D fast-field echo with water-selective excitation MRI. Another patient was successfully treated by minimally invasive endoscopic surgery.

Conclusions

Disc sequestration that mimics a tumor is difficult to diagnose preoperatively. As a non–invasive strategy, coronal MR images of 3D fast-field echo with water selective excitation is a helpful imaging tool for differentiating between diagnosis of disc sequestration that mimics a tumor and neurinoma prior to operation. If the disc fragment of mimicking tumor can be identified prior to operation, open surgery may not be necessary for all patients. Minimally invasive endoscopic surgery also is an alternative strategy.

Atypical Presentation of a Sequestered Posterolateral Disc Fragment

Sequestered disc fragments typically occur ventrally but can also migrate dorsally or intradurally. At times, atypical disc herniations can be misinterpreted on imaging as other lesions, such as neoplasms, hematomas, or abscesses. We present an uncommon case of a patient presenting with cauda equina syndrome secondary to an enhancing sequestered disc fragment mimicking a tumor.

The etiologies of low back pain in patients with lumbar disk herniation

BACKGROUND

Low back pain (LBP) is a common complaint in population that lowers the quality of life. The main etiology of LBP is recognized in about 20% of patients while it is attributed to lumbar disk herniation (LDH) in 80% of cases and causes some unnecessary lumbar surgeries without realizing the definite cause.

OBJECTIVES

This study was planned to evaluate the etiologies of LBP in patients who had LDH to clarify whether the disc herniation is the main cause of patients` pain or other diseases were responsible for this kind of pain.

MATERIALS AND METHODS

In this cross-sectional study, we analyzed the medical profiles of the patients with proven LDH in a private clinic in Mashhad City, Iran, between 2005 and 2012, for demographic and the etiologies of LBP with clinical and paraclinical studies. We also calculated the incidence of each etiology by SPSS 13.

RESULTS

In our study, among 1250 patients with proven LDH by MRI, 500 patients (40%) had chronic LBP and the most common causes of LBP were heavy constant working (40.2%), osteoporosis (35.6%), and sacroiliac joint pain (34.6%), consecutively. Interestingly, LDH had the ninth rank among the common cause of LBP.

CONCLUSIONS

In this study, we found that in spite of previous beliefs, discopathies were not common etiologies of LBP. Thus, even in patients with proven LDH by imaging studies, the physician should perform a thorough evaluation for other causes of LBP to avoid unnecessary lumbar surgeries.