Holocord Pilocytic Astrocytoma in an Adult: A Rare Case Report and Review of the Literature

Holocord pilocytic astrocytoma in a young woman with intracranial extension: case report and review of the MRI characteristics

INTRODUCTION

Pilocytic astrocytoma is a low-grade glioma more frequently seen in patients <20. It is pretty uncommon in the spinal cord. Rarely, astrocytoma may involve the most or total length of the spinal cord; in that case, they are called "holo-cord astrocytoma." In this case report, we are reporting the third holo-cord pilocytic astrocytoma in an adult patient and the first with an extension to the Magendie foramen.

CASE PRESENTATION

We presented a 24-year-old woman with complaints of progressively worsening neck and back pain since one year ago. The patient's MRI showed a very large intradural and intramedullary cystic lesion with a solid component within the spinal cord extending from the medulla to the conus medullaris. Partial resection of the solid part of the cervical portion of the tumor was performed. Histopathological evaluation of the resected tumor segments was compatible with grade I pilocytic astrocytoma. After one year of follow-up, neck and back pain has reduced, and neurological functions have improved.

CONCLUSION

Spinal cord pilocytic astrocytoma may present as a holo-cord tumor and can rarely extend to the intracranial fossa. Although this tumor does not arise from the central canal, in this case, it was extended through the Magendie foramen. Symptoms could be subtle despite extensive cord involvement. On MRI, this tumor presents as an intramedullary holo-cord cystic lesion intermixed with a solid component with a variable enhancement of the solid component.

Clinical Characteristics and Long-term Outcomes of Spinal Pilocytic Astrocytomas: A Multicenter Retrospective Study by the Neurospinal Society of Japan

OBJECTIVE

The characteristics, imaging features, long-term surgical outcomes, and recurrence rates of primary spinal pilocytic astrocytomas (PAs) have not been clarified owing to their rarity and limited reports. Thus, this study aimed to analyze the clinical presentation, radiological features, pathological findings, and long-term outcomes of spinal PAs.

METHODS

Eighteen patients with spinal PAs who were surgically treated between 2009 and 2020 at 58 institutions were included in this retrospective multicenter study. Patient data, including demographics, radiographic features, treatment modalities, and long-term outcomes, were evaluated.

RESULTS

Among the 18 consecutive patients identified, 11 were women and 7 were men; the mean age at presentation was 31 years (3-73 years). Most PAs were located eccentrically, were solid or heterogeneous in appearance (cystic and solid), and had unclear margins. Gross total resection (GTR), subtotal resection (STR), partial resection (PR), and biopsy were performed in 28%, 33%, 33%, and 5% of cases, respectively. During a follow-up period of 65 ± 49 months, 4 patients developed a recurrence; however, the recurrence-free survival did not differ significantly between the GTR and non-GTR (STR, PR, and biopsy) groups.

CONCLUSION

Primary spinal PAs are rare and present as eccentric and intermixed cystic and solid intramedullary cervical tumors. The imaging features of spinal PAs are nonspecific, and a definitive diagnosis requires pathological support. Surgical resection with prevention of neurological deterioration can serve as the first-line treatment; however, the resection rate does not affect recurrence-free survival. Investigation of relevant molecular biomarkers is required to elucidate the regrowth risk and prognostic factors.

Pilocytic Astrocytoma Arising from the Conus Medullaris in an Adult: A Case Report

Low-grade, sporadic, pilocytic astrocytomas (PAs) are rare spinal cord tumors diagnosed in adult patients. Their localization to the conus medullaris is exceedingly rare, having only been described in a limited number of case reports. Here, we describe a case of a 22-year-old female presenting with back pain, lower extremity weakness, hypoesthesia, and urinary incontinence. Imaging studies demonstrated a cystic lesion of the conus medullaris that was treated with subtotal resection and cyst-subarachnoid shunt placement. Final pathology report confirmed PA from the histology of surgical specimens. We discuss the current literature of conus medullaris lesions and their differential diagnosis.

Clinical characteristics and long-term surgical outcomes of spinal pilocytic astrocytoma: a report of twenty cases

BACKGROUND

Primary spinal pilocytic astrocytoma (PA) is an extremely rare low-grade astrocytoma with unclear natural history. The demographic characteristics, imaging features, and long-term surgical outcomes have not been clarified due to low prevalence and limited reports.

METHODS

A retrospective review within a single institution between 2004 and 2018 of all patients with pathologically proven PA was conducted. Patient data including demographics, radiographic features, treatment modalities, and long-term outcomes were evaluated.

RESULTS

Twenty consecutive patients were identified, and 16 (80%) were male patients, with a mean age at presentation of 29 ± 13 years. The lesion was primarily located in cervical (n = 10, 50%), thoracic (n = 7, 35%), cervico-thoracic junction (n = 2), and lumbar level (n = 1, 5%). The tumor had a mean extension of 4 ± 2 (1-7) vertebral segments. Most PAs were located eccentrically (n = 16, 80%), with most being heterogeneous in appearance (cystic and solid) or purely cystic (n = 14, 70%), and had unclear margins (n = 16, 80%). Eleven patients (55%) had associated syringomyelia. Gross total resection (GTR) was achieved in 11 (55%) patients, and subtotal resection (STR) in 9 (45%). During a mean follow-up of 104 ± 56 months, 2 patients died and recurrence was found in 4 patients (20%), translating to a mean progression-free survival of 21 ± 11 months.

CONCLUSION

Primary spinal PA is a rare entity with acceptable progression-free survival if treated appropriately. Surgical resection may provide reasonable prolongation of survival, and GTR should be achieved if possible. A close follow-up is recommended especially for residual lesions, and a further in-depth investigation of molecular biomarkers is needed to stratify risk and prognostic factors.

Intramedullary Masses of the Spinal Cord: Radiologic-Pathologic Correlation

Spinal cord tumors are a challenge for patients and neurosurgeons because of the high risk of neurologic deficits from the disease process and surgical interventions. Spinal cord tumors are uncommon, and approximately 2%-3% of primary intra-axial tumors of the central nervous system occur in the spinal cord. Primary intra-axial tumors are usually derived from neuroepithelial tissue, especially glial cells. This often leads to a classic intramedullary mass differential diagnosis of ependymoma or astrocytoma, which together constitute up to 70% of spinal cord tumors. For example, ependymomas occur predominantly in adults, and astrocytomas (specifically pilocytic astrocytomas) occur predominantly in children. While that is an excellent starting point, in order to refine the differential diagnosis, the authors review the radiologic-pathologic features of specific neoplastic categories and entities recognized by the World Health Organization (WHO) in the 2016 WHO Classification of Tumours of the Central Nervous System and a few additional congenital-developmental entities. Radiologists can add value by providing a reasonable preoperative differential diagnosis for the patient and neurosurgeon, in many cases by favoring the most common conditions, and in other cases by identifying radiologic features that may point toward a less common entity. Some of the less common entities include intramedullary myxopapillary ependymoma, spinal subependymoma, and spinal hemangioblastoma. Whenever possible, the characteristic imaging features and locations of these tumors are explained or traced back to the underlying cell of origin and findings seen at histopathologic examination.See discussion on this article by Buch.