Thoracic Intradural-Extramedullary Epidermoid Tumor: The Relevance for Resection of Classic Subarachnoid Space Microsurgical Anatomy in Modern Spinal Surgery. Technical Note and Review of the Literature

Isolated thoracic intradural extramedullary epidermoid cyst: A technical note

Background

Congenital, acquired, and iatrogenic spinal epidermoid cysts (EC) are very rare.

Methods

A 62-year-old female patient presented with a 5-month history of progressive paraparesis leading to paraplegia secondary to a posterior compressive intradural extramedullary lesion at the T7 level. The patient underwent a laminectomy/durotomy for gross total tumor excision.

Results

Histopathology confirmed the lesion was an epidermoid cyst. Although her spasticity improved within 5 weeks, she only regained partial lower extremity motion (i.e., 3/5 motor function).

Conclusion

Patients presenting with the acute/subacute onset of paraparesis secondary to spinal EC should undergo timely gross total cyst resections to optimize neurological outcomes.

Case Report: Recurrence of an Extradural Spinal Epidermoid Cyst Following Surgical Excision in a Dog

Congenital epidermoid cysts are slow-growing, mass lesions caused by the abnormal inclusion of neuroectodermal tissue within the developing central nervous system. Subtotal excision of epidermoid cysts increases the risk of early recurrence of clinical signs. A 4-year-old female spayed boxer was presented with a 4-month history of ambulatory paraparesis and proprioceptive ataxia. Neurological examination localized a T3-L3 myelopathy. MRI revealed a T1 iso- to hypointense, T2 and FLAIR hyperintense, rim-enhancing mass at the level of the T9-T10 vertebrae resulting in extradural compression of the spinal cord. This was histopathologically confirmed as an extradural epidermoid cyst following subtotal excision. MRI performed 2 months post-operatively revealed a significant decrease of the lesion volume. The dog was neurologically normal following the surgery however re-presented 28 months later with recurrence of clinical signs. A 28-month post-operative MRI revealed substantial enlargement of the epidermoid cyst. The dog was subsequently taken for repeat decompressive surgery. At 6 months from the repeat surgery, the dog was neurologically static with mild proprioceptive deficits. The case report highlights the clinical and MRI features of a recurrent extradural spinal epidermoid cyst treated by subtotal excision.

A Case of Scheuermann’s Disease Co-Occurrence with Idiopathic Scoliosis and Intradural-Extramedullary Epidermoid Cyst: The First Case Report in Literature

Background and importance: Scheuermann’s disease (SD), intradural-extramedullary epidermoid cysts and idiopathic scoliosis (IS) are all rare conditions. The co-occurrence of the three condition on one case has not been reported in literature before. We describe an extremely rare case of SD co-occurrence with IS and intradural-extramedullary epidermoid cyst, which is the first in the literature. Clinical presentation: A 13-year old boy and his parents presented at Honghui Hospital complaining of progressive hyperkyphosis for 5 years and back pain for 2 months. Thorough medical examination and radiology confirmed the diagnosis of SD kyphosis, IS, and intradural-extramedullary epidermoid cyst. Medical panel with spine surgeons, oncologists, neurosurgeons, histopathologists and radiologists were consulted. Tumor excise, kyphosis recorrection and spine reconstruction surgery was conducted. Postoperative histological examination detected desquamation of keratin from the epithelial lining and stratified squamous epithelium without skin adnexa. The boy was ambulant 2 days postoperative with walking aids. Conclusion: This is the first case report of Scheuermann’s disease (SD) co-occurrence with idiopathic scoliosis (IS) and intradural-extramedullary epidermoid cyst. The co-occurrence of intradural epidermoid cyst, SD and IS might not be a coincidence, indicating a kind of genetic etiology need to be illuminated.

Anatomy of the human spinal cord arachnoid cisterns: applications for spinal cord surgery

OBJECTIVE

The goal in this study was to describe the overall organization of the spinal arachnoid mater and spinal subarachnoid space (SSAS) as well as its relationship with surrounding structures, in order to highlight spinal cord arachnoid cisterns.

METHODS

Fifteen spinal cords were extracted from embalmed adult cadavers. The organization of the spinal cord arachnoid and SSAS was described via macroscopic observations, optical microscopic views, and scanning electron microscope (SEM) studies. Gelatin injections were also performed to study separated dorsal subarachnoid compartments.

RESULTS

Compartmentalization of SSAS was studied on 3 levels of axial sections. On an axial section passing through the tips of the denticulate ligament anchored to the dura, 3 subarachnoid cisterns were observed: 2 dorsolateral and 1 ventral. On an axial section passing through dural exit/entrance of rootlets, 5 subarachnoid cisterns were observed: 2 dorsolateral, 2 lateral formed by dorsal and ventral rootlets, and 1 ventral. On an axial section passing between the two previous ones, only 1 subarachnoid cistern was observed around the spinal cord. This compartmentalization resulted in the anatomical description of 3 elements: the median dorsal septum, the arachnoid anchorage to the tip of the denticulate ligament, and the arachnoid anchorage to the dural exit/entrance of rootlets. The median dorsal septum already separated dorsal left and right subarachnoid spaces and was described from C1 level to 3 cm above the conus medullaris. This septum was anchored to the dorsal septal vein. No discontinuation was observed in the median dorsal arachnoid septum. At the entrance point of dorsal rootlets in the spinal cord, arachnoid trabeculations were described. Using the SEM, numerous arachnoid adhesions between the ventral surface of the dorsal rootlets and the pia mater over the spinal cord were observed. At the ventral part of the SSAS, no septum was found, but some arachnoid trabeculations between the arachnoid and the pia mater were present and more frequent than in the dorsal part. Laterally, arachnoid was firmly anchored to the denticulate ligaments' fixation at dural points, and dural exit/entrance of rootlets made a fibrous ring of arachnoidodural adhesions. At the level of the cauda equina, the arachnoid mater surrounded all rootlets together-as a sac and not individually.

CONCLUSIONS

Arachnoid cisterns are organized on each side of a median dorsal septum and compartmentalized in relation with the attachments of denticulate ligament and exit/entrance of rootlets.

An Epidermoid Cyst of the Thoracic Spine in an Elderly Patient

BACKGROUND

Spinal epidermoid cysts are very rare tumors, especially in the thoracic spine; they represent 0.8% of all spinal epidermoids. In adult cases, they are often associated with surgical procedures such as lumbar puncture. We report a rare case of spinal epidermoid cyst in the thoracic spine of an elderly patient who had never undergone lumber puncture, thoracic spinal surgery, or trauma.

CASE DESCRIPTION

A 78-year old woman presented with a 1-month history of rapidly progressive impairment of sensation in both the lower limbs, with gait disturbance. She had no history of spinal surgery, trauma, or lumbar puncture. Her past medical history was unremarkable. Magnetic resonance imaging of the whole spine revealed an intraspinalextramedullary tumor at the Th 1-2 level. Diffusion-weighted imaging revealed significant homogeneous high intensity. We performed complete resection without damaging the spinal cord or nerve roots. The final histological examination indicated epidermoid cyst without malignancy. Her gait disturbance was completely resolved at 4-month follow-up.

CONCLUSIONS

Epidermoid cysts must be considered among spinal tumors in elderly patients. Early detection by diffusion-weighted imaging and complete resection may lead to good neurological outcome.

Intradural spinal tumors in adults-update on management and outcome

Among spinal tumors that occur intradurally, meningiomas, nerve sheath tumors, ependymomas, and astrocytomas are the most common. While a spinal MRI is the state of the art to diagnose intradural spinal tumors, in some cases CT scans, angiography, CSF analyses, and neurophysiological examination can be valuable. The management of these lesions depends not only on the histopathological diagnosis but also on the clinical presentation and the anatomical location, allowing either radical resection as with most extramedullary lesions or less invasive strategies as with intramedullary lesions. Although intramedullary lesions are rare and sometimes difficult to manage, well-planned treatment can achieve excellent outcome without treatment-related deficits. Technical advances in imaging, neuromonitoring, minimally invasive approaches, and radiotherapy have improved the outcome of intradural spinal tumors. However, the outcome in malignant intramedullary tumors remains poor. While surgery is the mainstay treatment for many of these lesions, radiation and chemotherapy are of growing importance in recurrent and multilocular disease. We reviewed the literature on this topic to provide an overview of spinal cord tumors, treatment strategies, and outcomes. Typical cases of extra- and intramedullary tumors are presented to illustrate management options and outcomes.