PTPS-04LUMBAR SPINAL ATYPICAL TERATOID RHABDOID TUMOR- CASE REPORT

INTRODUCTION: Atypical Teratoid Rhabdoid tumor (AT/RT) is a rare, highly aggressive pediatric tumor of the central nervous system with a dismal prognosis. Although there is sufficient literature on brain AT/RT, spinal AT/RT continues to be a rare entity with lumbar location even less frequently reported. We report a recently diagnosed case of a lumbar spinal AT/RT in an African American child in our institution. CASE REPORT: A 30-month-old African American male child with multiple comorbidities presented with the inability to ambulate, encopresis and urinary dribbling. MRI showed an intradural extramedullary mass extending downwards from L3-4 level. He underwent L3-S2 laminoplasty. The surgically resected mass was marked by sheets of cells with large nuclei and prominent nucleoli. The tumor cells stained with antibodies to synaptophysin and CAM 5.2 and showed an absence of immunoreactivity to INI-1 antibody. A diagnosis of a WHO grade IV AT/RT was rendered. There was no mutation detected in the SMARCB1 gene on comprehensive analysis of blood. Patient is currently being treated according to the Medical University of Vienna ATRT-protocol (MUV-ATRT) with no evidence of tumor recurrence 8 months after surgery. DISCUSSION: Although not observed in all the cases, mutations of hSNF5/INI1, also known as SMARCB1 gene on chromosome 22q11, is pathognomic for AT/RT. Recent studies have suggested that the inactivation of INI1 might be associated with a poor prognosis. It is not known if spinal AT/RTs routinely have the chromosomal 22q abnormality frequently seen with brain AT/RT or if the two entities even have a different prognosis. More cases need to be reviewed to differentiate spinal from brain AT/RT to determine an effective prognostic marker and treatment strategy for patients with this rare tumor.