A case of Embryonal Tumor with Abundant Neuropil and True Rosettes (ETANTR): a distinct genetic locus with an excellent outcome (P3.6-010)

Objective: NA Background: ETANTR is a rare, clinically aggressive embryonal tumor occurring under 4 years of age with significantly poor prognosis. There are less than 70 cases reported since 2000. The median survival has been reported to be less than 9 months and few that survived longer had neurological deficits. We present a case of ETANTR with an excellent outcome. Our patient had an amplification of miRNA on Chromosome 19 but with a distinct locus (19q13.41) compared to previous cases reported in literature. Design/Methods: Case: Previously healthy 3-year-old right handed boy presented after a generalized tonic clonic seizure at night. Neurological exam was benign. EEG showed some transient left temporal slowing and central spikes while drowsy and asleep. MRI showed 5.5 × 5.2 × 5.1 cm mass in the white matter of left frontal lobe that crossed midline with 9 mm shift and no evidence of metastasis to spine. CT brain done at the time of birth due to neonatal sepsis was completely normal denoting rapid growth within 3 years. Patient underwent craniotomy with complete excision of the tumor. Histopathology showed abundant neuropil and focal ependymoblastic rosettes. It was positive for LIN28. Molecular analysis showed amplification of the miRNA locus on chromosome 19 (C19MC). Patient received intensive induction chemotherapy followed by autologous PBSC (peripheral blood smear cells) and GCSF (granulocyte cell stimulating factor). Subsequent MRI brain at 3, 6 and 12 months showed no recurrence of tumor and patient is doing well with no neurological deficits. Results: NA Conclusions: Until now, genetic hallmark reported in all previous cases is the amplification of the microRNA cluster (C19MC) at 19q13.42 compared to our case which has a unique locus i.e. microRNA cluster at 19q13.41 on FISH analysis. We hypothesize that this unique locus might have contributed to the excellent outcome in our case. Disclosure: Dr. Nemade has nothing to disclose. Dr. Knowles has nothing to disclose. Dr. Payne has nothing to disclose. Dr. Nahar has nothing to disclose.