Primary primitive neuroectodermal tumor of the conus medullaris in an elderly patient: a case report and review of the literature

Analysis of Clinical, Imaging, and Pathologic Features of 36 Patients with Primary Intraspinal Primitive Neuroectodermal Tumors: A Case Series and Literature Review

BACKGROUND AND STUDY AIMS

 Primary intraspinal primitive neuroectodermal tumors (PNETs) account for ∼0.4% of all intraspinal tumors, but information about these tumors in the medical literature is limited to single case reports. We report four cases of primary intraspinal PNETs and present a systematic literature review of the reported cases.

MATERIALS AND METHODS

 We retrospectively reviewed and analyzed the clinical data of 4 patients with primary intraspinal PNETs who underwent neurosurgical treatment at our clinic between January 2013 and January 2020, and of 32 cases reported in the literature.

RESULTS

 The female-to-male ratio was 2.6:1. The mean patient age was 21.42 ± 15.76 years (range: 1-60 years), and patients <36 years of age accounted for 83.30% of the study cohort. Progressive limb weakness and numbness were the chief symptoms (accounting for ∼55.6%). The mean complaint duration was 0.89 ± 0.66 months for males and 2.72 ± 3.82 months for females (p = 0.028). Epidural (41.7%) was the most common site, and thoracic (47.3%) was the most frequent location. Most PNETs were peripheral, and magnetic resonance imaging (MRI) appearance was isointense or mildly hypointense on T1-weighted images and hyperintense on T2-weighted images. Homogeneous contrast enhancement was observed. The 1-year survival rate of patients who underwent chemoradiation after total or subtotal lesion resection was better compared with patients who did not undergo chemotherapy, radiotherapy, or total or subtotal resection. The modality of treatment was associated with survival time (p = 0.007).

CONCLUSION

 Primary intraspinal PNETs mainly occur in young people with a female preponderance. In patients with a rapid loss of lower limb muscle strength and large intraspinal lesions on MRI, PNETs should be considered. Surgical resection and adjuvant radio chemotherapy are key prognostic factors.

Primary intraspinal extradural primitive neuroectodermal tumor: A rare case

Primitive neuroectodermal tumors (PNETs) are aggressive childhood malignancies and are difficult to treat. Primary intraspinal PNETs are rare. These patients have poor prognosis with short survival time even after surgery and chemoradiation. As there are no standard guidelines exist for the management of these tumors, a multidisciplinary approach has been employed with varying success. According to the review of literature, only few cases of primary intraspinal extradural PNETs have been reported. Herein, author has described a case of intraspinal, extradural PNET.

Primary spinal primitive neuroectodermal tumor on MR imaging

Neoplasms in the region of filum terminale are not uncommon. Myxopapillary ependymoma is the commonest tumor at this location. The differentials reported for this entity are nerve sheath tumor, meningioma, paraganglioma, intradural metastases, lymphoma, other varieties of ependymoma, subependymoma, astrocytoma, ganglioglioma, hemangioblastoma, and primitive neuroectodermal tumor (PNET). PNET may very rarely present as an intradural thoracolumbar mass. We present pre- and post-therapy magnetic resonance imaging (MRI) features of a patient with proven primary spinal primitive neuroectodermal tumor (PSPNET) of peripheral subtype.

Comparison of Primary Spinal Central and Peripheral Primitive Neuroectodermal Tumors in Clinical and Imaging Characteristics and Long-Term Outcome

OBJECTIVE

Primary spinal primitive neuroectodermal tumors are extremely rare entities. The purpose of this study was to analyze the differences in clinical and imaging characteristics and outcomes between primary spinal central PNETs (cPNETs) and peripheral PNETs (pPNETs).

METHODS

There were 25 consecutive patients with primary spinal primitive neuroectodermal tumors enrolled. The diagnosis was cPNET in 6 patients with negative CD99 expression and pPNET in 19 patients with positive CD99 expression. Gross total resection (GTR) was achieved in 12 patients, subtotal resection was performed in 9 patients, and partial resection was performed in 4 patients. Postoperative chemotherapy was given to 14 patients, and radiotherapy was given to 16 patients.

RESULTS

The age at diagnosis was significantly younger in the cPNET group (mean 12.8 years) compared with the pPNET group (mean 22.5 years) (P = 0.040); the 2 pathologies did not show a significant difference in prognosis. GTR (P = 0.041), radiotherapy (P = 0.008), and GTR with radiotherapy (P = 0.009) were significant factors leading to a higher 2-year survival rate. Kaplan-Meier analysis showed that radiotherapy (P < 0.001) and GTR with radiotherapy (P = 0.040) resulted in a longer median survival time. Patients who underwent GTR, chemotherapy, and radiotherapy all together had the highest 1-year (100.0%) and 2-year (71.4%) survival rates and the longest median survival time (32 months).

CONCLUSIONS

Patients with spinal cPNETs were younger compared with patients with pPNETs. The prognosis of spinal cPNETs and pPNETs was poor with no significant difference between the entities. The most beneficial treatment modality is GTR combined with adjuvant radiotherapy and chemotherapy.

Intracranial metastasis from primary spinal primitive neuroectodermal tumor

Primary spinal primitive neuroectodermal tumors (PNET) are rare tumors, with only 94 cases reported till date. Metastasis to brain from a spinal PNET is even rarer. In the present report, we evaluate the pathology and treatment of solitary intracranial metastasis from spinal PNET in a 22-year-old female who presented with headache and left hemiparesis and was diagnosed to have right parietal parasagittal tumor. She has been previously diagnosed to have cervicothoracic primary spinal PNET, and was treated by surgery, radiotherapy, and chemotherapy seven years back. The intracranial tumor has been removed and pathological examination confirmed as PNET. She received radiotherapy and chemotherapy with ifosfamide and etoposide, following surgery for the right parietal PNET. At 20 months follow-up, patient is stable and has no recurrence of the disease. Critical review of reported cases of primary spinal PNET metastsising to brain was done.