Neural Foraminal Lesions: An Imaging Overview

MRI of difficult discs

Diagnosis of disc herniation is a daily task for radiologists. Although diagnosis is usually straightforward, it may become more difficult due to disc location. Disc herniations in the neural foramen or lateral to it can be overlooked if sagittal images are not obtained far enough laterally, and are often best seen on coronal images. Intradural disc herniations should be recognised preoperatively by their distinctive shape; recognition prepares the surgeon for the need to perform a durotomy and dural repair. Sequestered discs are often lentiform and inconspicuous on sagittal images. They can be missed if axial images are obtained only through the level of the intervertebral disc. Mimics of disc herniation must also be kept in mind when reviewing magnetic resonance imaging (MRI) studies: these include disc osteophyte complex, epidural haematoma, facet joint cyst, and tumours such as meningioma, nerve sheath tumours, and metastases.

Percutaneous Full Endoscopic Management of Spinal Foraminal Schwannomas: Case Series

BACKGROUND

Schwannoma, a benign peripheral nerve sheath tumor, is perhaps only secondary to degenerative pathology as the most common lesion at neural foramen. The surgical dilemma here is either risking nerve injury because of inadequate exposure or the need for internal fixation because of facet joint sacrifice.

OBJECTIVE

To evaluate the feasibility and safety of management of foraminal schwannomas by percutaneous full-endoscopic technique.

METHODS

A single-center retrospective review was conducted on patients who underwent full-endoscopic resection of neural foraminal schwannomas. Tumors were grouped into either medial type or lateral type based on relevant location to the neural foramen, and respective surgical approaches were adopted. Data including preoperative neurological status, tumor size, surgery time, the extension of resection, and clinical outcomes were collected. The learning curve was plotted as surgical time/tumor size against case number.

RESULTS

A total of 25 patients were treated between May 2015 and March 2022. Gross total resection was achieved in 24 patients, and near-total resection in 1 case, with 1 patient experienced transient voiding difficulty. No tumor recurrence or spinal instability was detected in the short-term follow-up (median follow-up 22 months, range 3 months-6 years). Surgical efficiency improved with the number of cases operated on and remained stable after the initial 10 cases.

CONCLUSION

Percutaneous full-endoscopic technique is a safe and minimally invasive technique for the resection of foraminal schwannomas.

Pure lumbar foraminal cavernous malformation in a patient with Cowden syndrome-a case report

BACKGROUND

Spinal cavernous malformations (CMs) are slow flow venous vascular malformations which can occur in vertebral body, epidural space or intramedullary. Only 7 cases were described confined in foraminal space. Cowden syndrome (CS) is an autosomal dominant genodermatosis that may present and develop vascular malformations, which include CM. They were found intracranial, and rarely visceral. No association with spinal CM and CS has been reported to date.

CASE DESCRIPTION

A 46-year-old patient with CS came to our attention with a L5 radiculopathy secondary to a slow-growing intra-foraminal mass lesion, with bony scalloping. The lesion mimicked a schwannoma at radiological imaging and intraoperative findings. En bloc resection with root sacrifice was performed. No excessive bleeding was observed. After surgical resection, anatomical pathology demonstrated a CM. Postoperative review of neuroimaging revealed features compatible with chronic resolved peripheral haemorrage. The patient had no intra- or post-operative complications, and an immediate relief of symptoms was observed. The follow-up spinal magnetic resonance imaging (MRI) obtained 3 months after surgery, demonstrated the total removal of the lesion.

CONCLUSIONS

CMs can be confined to foraminal space and associated with CS. They may mimic peripheral nerve sheath tumors. Diagnosis may be challenging. No pathognomonic imaging features were found. Complete resection with root sacrifice seems to be a safe and efficient technique.

Tumours involving the neural foramina in children: beyond neuroblastoma

AIM

To characterise tumours that involve the neural foramina in children, including prevalence, demographics, and imaging features.

MATERIAL AND METHODS

This retrospective single-centre study comprised 36 boys and 34 girls who presented with spinal or paraspinal lesions involving the neural foramina. Two certified radiologists reviewed the imaging features, including the level of spinal involvement, the number of involved foramina, foraminal widening, tumour epicentre, and cord compression. Medical charts were reviewed for patients' demographics and tumour pathology. Tumours were classified as benign or malignant, and neuroblastomas were further classified as low or intermediate risk versus high risk.

RESULTS

Thirty-three (47%) of the patients had neuroblastic tumours. Fourteen (20%) of the patients had sarcomas (mainly Ewing sarcoma). Other less common aetiologies included neurofibromas, germ cell tumours, Langerhans cell histiocytosis and haemangiomas. Neuroblastic tumours were particularly common in the thoraco-lumbar region, and considerably less prevalent in the sacral and cervical regions. Additional features, such as foraminal widening, the number of foramina involved, and cord compression, did not help discriminate between neuroblastic and non-neuroblastic tumours. Most tumours (80%) were malignant. Most benign tumours (>50%) were associated with a genetic predisposition syndrome.

CONCLUSION

In evaluating neoplasms that involve the neural foramina in children, neuroblastic tumours are most common. Nevertheless, other aetiologies should be considered, mainly sarcomas. Most lesions in children are malignant. When encountering a benign mass, genetic counselling should be considered.

Spinal paraganglioma as unusual finding in von Hippel-Lindau disease

A 20-year-old patient with a history of von Hippel-Lindau disease reported on thoracic back pain radiating to the left shoulder for 10 weeks. Magnetic resonance imaging revealed a progressive contrast-enhancing tumor (14 × 21 × 28 mm) compressing the spinal cord and extending into the left neural foramen at T5/6. After embolization of supplying vessels, the tumor was completely resected via hemilaminectomy of T5. The postoperative course was uneventful without surgery related morbidity. The pathological examination disclosed a paraganglioma WHO grade I. We discuss the differential diagnoses and pitfalls of this unexpected finding in this patient with von Hippel-Lindau disease.