Atypical Teratoid Rhabdoid Tumor of the Cauda Equina in a Child: Report of a Very Unusual Case

Epidemiology, Characteristics, and Prognostic Factors of Primary Atypical Teratoid/Rhabdoid Tumors in the Spinal Canal: A Systematic Review

Primary atypical teratoid/rhabdoid tumors (AT/RTs) in the spinal canal are rare central nervous system (CNS) neoplasms that are challenging to diagnose and treat. To date, there has been no standard treatment regimen for these challenging malignant tumors. Thus, we conducted this research to explore potential prognostic factors and feasible treatment modalities for improving the prognosis of these tumors. Articles were retrieved from the PubMed, MEDLINE, and Embase databases, using the keywords "atypical teratoid/rhabdoid tumor," "rhabdoid tumor," "spine," "spinal," "spinal neoplasm", and "spinal cord neoplasm." All eligible cases demonstrated SMARCB1-deficient expression validated by pathological examination. We collected and analyzed data related to clinical presentation, radiological features, pathological characteristics, treatment modalities and prognosis via Kaplan-Meier and Cox regression analyses. Thirty-six articles comprising 58 spinal AT/RT patients were included in the study. The median progression-free survival (PFS) and overall survival (OS) were 18 and 22 months, respectively. Kaplan-Meier analysis demonstrated significant survival improvements for OS in the nonmetastasis, male, radiotherapy and intrathecal chemotherapy groups as well as for PFS in the chemotherapy and radiotherapy groups. Multivariate analysis revealed that chemotherapy and radiotherapy were prognostic factors for improved PFS, and that intrathecal chemotherapy reduced the risk of mortality. Spinal AT/RTs are uncommon malignant entities with a dismal survival rate. Although our review is limited by variability between cases, there is some evidence revealing potential risk factors and the importance of systematic chemotherapy, intrathecal chemotherapy and radiotherapy in spinal AT/RT treatment modalities.

Clinical diagnostic and radiographic features of primary spinal atypical teratoid rhabdoid tumors tumor in a pediatric patient: A case report and review of the literature

Atypical teratoid rhabdoid tumors (ATRTs) are rare embryonal tumors comprising 1-2% of all pediatric CNS neoplasms. Spinal ATRTs are even more uncommon, accounting for 2% of all reported ATRT cases. Despite their rarity, ATRTs affect young children disproportionately and are characterized by a high malignant potential due to a heterogeneous cellular composition and inactivating mutations in the SMARCB1 (90%) and SMARCA4 (10%) genes. A 15-month-old female presented with a 2-week history of decreased lower extremity movement and new-onset need for assistance with ambulation. MRI lumbar spine revealed a contrast-enhancing intradural mass at the L3-L4 level with iso-intensity on T1 and T2 sequences. The patient subsequently underwent subtotal tumor resection (∼80%) given concerns for maintaining neurological function. Final pathology was consistent with spinal ATRT, and she later underwent adjuvant chemoradiation therapy per ACNS0333 protocol. She has since remained in remission with age-appropriate developmental milestones over the past 2 years. ATRTs should be considered in the differential diagnosis of intradural spinal lesions, especially in the pediatric patient population. Clinical course, presentation, and diagnosis is often delayed due to the rarity of these tumors, but contrasted craniospinal MRI is key for diagnosis and histopathology with IHC staining showing loss of INI is confirmatory. While gross total resection is the goal, maximal safe tumor resection should be prioritized in order to preserve neurological function. Adjuvant chemoradiation following gross total/subtotal resection has been shown to significantly improve overall survival.

Atypical Teratoid/Rhabdoid Tumor of the Conus Medullaris

INTRODUCTION

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare tumor of the central nervous system, especially when involving the spinal column or spinal cord.

CASE PRESENTATION

We present a case of a 5-year-old girl with progressive bilateral lower extremity pain found to have a discrete nodular lesion of the conus with mild heterogeneous enhancement. Surgical decompression and resection demonstrated a pathologic tumor consistent with AT/RT with loss of INI1 protein on immunohistochemistry.

DISCUSSION AND CONCLUSION

AT/RT lesions of the conus medullaris are exceedingly rare and associated with extensive disease. We report a rare case of AT/RT with selective involvement of the conus medullaris, as well as describe the surgical, radiographic, and pathologic findings of this tumor.