Clinicopathological characteristics and outcomes in Embryonal tumor with
multilayered rosettes: a decade long experience from a tertiary care
centre
Abstract
Background: Embryonal tumor with multilayered rosettes (ETMR) are a
heterogenous group clinically, pathologically and topographically. Due
to limited cases, data regarding its molecular genetics, pathology and
prognostic factors is evolving. We retrospectively analysed our cohort
of ETMR over last decade in order to study their clinicopathological
characteristics and outcome. Methods: Our cohort consisted of patients
diagnosed with Embryonal tumor with abundant neuropil and true rosettes
(ETANTR)/Ependymoblastoma (EBL)/ Medulloepithelioma (MEPL) over the past
decade. Clinical details, including outcome and imaging data was
retrieved. Histological analysis including immunohistochemical work-up
was performed. Results: Cohort included 15 patients with age range
between 1-28 years and M:F ratio of 1.5:1. Supratentorial location
predominated in comparison to tumors arising in posterior fossa. ETANTR
and EBL patterns were equally distributed (40% each), followed by one
case each of mixed pattern (EBL+ETANTR), MEPL and embryonal tumor,
unclassified. All tumors readily expressed LIN 28A and INI-1 was
retained. Recurrence with evidence of glial and rhabdoid differentiation
was noted in a single patient 9 months following resection. Follow-up
period ranged from 1-31 months, with overall median survival of 6.4
months. Eight patients were planned for adjuvant treatment following
surgery, of which only four could complete it. All patients, except for
one, succumbed to the disease. Conclusions: ETMR have a heterogenous
morphology and gathers ETANTR, EBL, MEPL within its spectrum. Following
treatment, the recurrent tumor may feature glial/rhabdoid
differentiation. LIN28A is expressed in all cases, however should be
interpreted in context of histology. Prognosis of ETMR remains dismal
despite multimodal therapy.