Disseminated Craniospinal Myxopapillary Ependymoma Treated with Biopsy and Adjuvant Radiation Therapy: A Case Report and Review of Literature
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.314566
Source of Support: None, Conflict of Interest: None
Myxopapillary ependymoma (MPE) of the conus medullaris, cauda equina, and the filum terminale of the spinal cord are generally considered as benign slow-growing tumors (WHO grade 1). While complete resection has been suggested for better prognosis, our case had diffuse craniospinal dissemination, and we could only do biopsy followed by adjuvant radiation therapy (RT) with satisfactory outcome. We have discussed the clinical presentation, radiological features, and management strategies of this disease.
An eighteen-year-old man presented to the outpatient department with complaints of weakness and tightness in the bilateral lower limbs since six months. The weakness was progressive and he became bedridden a month before presenting to us. Upon examination, the upper limbs were normal and bilateral lower limb was spastic (modified Ashworth grade III). The bulk was normal and power was 1/5 (MRC grade). Upon sensory examination, there was graded sensory loss below the neck with intact perianal sensations. The posterior columns were found to be involved and hyperreflexia was seen in both the lower limbs.
Magnetic resonance imaging (MRI) of the spine revealed diffuse leptomeningeal lesion involving the entire spinal cord. The lesion was hypointense on T1W and hyperintense on T2W with areas of cystic changes within the lesion. The heterogeneous enhancement of the lesion was noted after intravenous gadolinium contrast administration [Figure 1] and [Figure 2]. Scalloping of the lumbar vertebral bodies were also seen. MRI brain showed similar diffuse leptomeningeal enhancing lesion in the peri-mesencepahlic area, bilateral sylvian fissure, anterior interhemispheric fissure and cerebellopontine cisterns [Figure 3]. Based on MRI, our working diagnosis was diffuse leptomeningeal glioneuronal tumor. In view of the diffuse involvement by the lesion involving craniospinal subarachnoid spaces, aggressive resection of the spinal component was not planned. The treatment strategy involved getting a histopathological diagnosis followed by treatment planning. So, the patient underwent L3-4 laminectomy and biopsy of the lesion. The lesion was diffuse, soft, and mildly vascular. The tumor was completely intradural and there was no plane do dissect the nerve roots and was adherent. Therefore, only partial decompression and biopsy were done.
Histopathological examination showed that tumor was composed of papillary fragments with ependymal cells arranged in single layers and cribriform patterns around a central hyalinized vascular core. The stroma showed extensive cystic and myxoid change and mitotic activity was inconspicuous. Immunohistochemistry (IHC) tests were performed with the following results: GFAP was positive in the tumor cells and EMA was showing focal dot positivity. Pan cytokeratin was negative and MIB-1 labelling was scattered [Figure 4]. The final impression of MPE (WHO grade I) was made based on the above histopathological findings and IHC markers.
The postoperative period was uneventful and he was discharged in the same neurological status with early, aggressive physiotherapy and neurorehabilitation. The patient received a palliative craniospinal irradiation of 36Gy in 12 fractions. At last follow up (18 months), the patient had significant recovery in his neurological status. He is ambulatory with minimal support and independent for the basic activity of daily living. The current McCormick's grade improved to 2 as compared to the preoperative grade of 4. Follow up MRI at 18 months showed significant reduction in the size of the lesion and leptomeningeal enhancement.
In the spinal cord, the most common location for ependymoma is the lower spine and conus region followed by the cervical spine. MPEs usually appear hypointense to isointense on T1 weighted images and hyperintense on T2-weighted images. The heterogeneous signal may appear due to the cystic or hemorrhagic changes. Ependymoma usually shows homogeneous contrast enhancement. The tumoral cyst can be identified from the nontumoral cyst as its wall shows enhancement on contrast study.
MPE usually has a good plane of cleavage from the surrounding neural tissue; so, the gross total removal can be achieved without any additional neurological deficit to patient. In patients with ependymoma, the outcome depends upon the extent of tumor removal and functional status of the patients at the time of surgery. The most important prognostic factor in determining the postoperative neurological status in the long-term is the patient's functional status at surgery; hence, the need for an early diagnosis is emphasized.
MPEs are known for metastasis. Local recurrence as well as distant spread has been seen after surgery. There have been reports regarding the dissemination of MPE along the craniospinal axis. Tumor handling, capsular breach, and CSF spread are the proposed theories. A case of spontaneous craniospinal dissemination from the spinal MPE has been described by Straus et al. Mridha et al. have reported the metastasis of the spinal MPE in cerebellopontine angles 3 years after the spinal surgery in a 13-year-old child without the recurrence at the primary site. Khalatbari et al. have reported the dissemination of the filum MPE after spinal trauma in a child. Davis and Barnard have reported three cases of MPE dissemination along the neuraxis following prior subtotal tumor resection. Similarly, Dickerman et al. described the metastasis of spinal MPE in a 47-year-old man within six weeks of surgery. Bleed within the lesion is also a possible cause causing the spontaneous dissemination of the lesion. The hemorrhage causes tumor expansion and increases the intratumoral pressure that results in capsule rupture.
In our case, we could only do biopsy of the lesion from the lumbar region as the tumor was deemed nonresectable with obvious intracranial disease. Histopathology was consistent with myxopapillary ependymoma. Based on imaging and histopathological diagnosis, the patient was subjected to adjuvant RT.
The role of upfront RT in spinal MPEs remains debatable. A study from MD Anderson consisting of 35 cases of spinal MPEs found no statistical difference in the extent of initial surgery in relation to overall survival (OS) or progression-free survival (PFS). However, adjuvant RT administered regardless of the extent of the surgery showed better local control rates and PFS at 10 years. Gomez et al. reviewed the records of 37 patients from UCSF who had spinal ependymoma and of whom seven had MPE. These investigators reported that the extent of surgery was significantly correlated only with the PFS and that RT was not correlated with PFS. It is important to note that the UCSF series includes other ependymoma histological types and not just MPE. Chao et al. in their study of 37 cases of spinal MPEs have concluded that a less-aggressive resection to maintain functionality and delaying RT at the time of recurrence is a reasonable approach. This may maximize patient quality of life by delaying any sequelae from aggressive surgery or side effects from radiation. As we did not resect the tumor, our patient was subjected to adjuvant RT immediately after surgical biopsy. He improved significantly both clinically and radiologically at 18 months follow up. Tobias et al. recommended the serial imaging for detecting tumor recurrence and stabilization of progressive spinal deformity. We have planned for further biannual imaging and clinical examination of the patient to rule out the worsening of the disease.
Ependymomas are a heterogenous group of tumors with varying clinical, imaging, and histomorphological presentations. The standard of care is complete, bur safe resection of tumor. Many studies have demonstrated the advantage of detecting genetic alterations in predicting prognosis and survival. Further genetic analysis of these rare diffusely spreading myxopapillary ependymomas may throw some light on its genetics and molecular signatures.
To conclude, diffuse dissemination of MPE at initial presentation is an extremely rare condition. Complete excision is advised for the isolated MPE and it is possible in most of the cases. However, the management strategy is not clear when the lesion presents with diffuse craniospinal leptomeningeal involvement as in our case. Biopsy followed by adjuvant RT proved to be beneficial in our case in terms of clinical as well as radiological improvement upon 18 months follow up. Long-term follow-up and further studies are required to propose the management guidelines for such rare tumor.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]