An atypical location of pineoblastoma RB1 subgroup without pineal or retinal tumor

Abstract

Purpose: To describe the clinical and imaging features of a sellar-suprasellar pineoblastoma RB1 subgroup without pineal or retinal involvement.

Case report: An 11-month-old girl presented to the emergency department with fever, rhinorrhea, vomiting, altered level of consciousness, and one seizure. Head CT and brain MRI demonstrated a large lobulated mass with calcifications and heterogeneous enhancement in the suprasellar region causing mass effect to the ventricular system and hydrocephalus. Histology revealed a CNS embryonal tumor not otherwise specified (NOS) with small round nuclei with mitotic activity and necrosis. DNA methylation analysis classified the tumor in the pineoblastoma RB1 subgroup.

Conclusion: Pineoblastoma RB1 subgroup should be considered in the differential diagnosis of large sellar-suprasellar masses with calcifications and heterogeneous enhancement in children younger than 18 months even in cases of absent pineal or retinal involvement. Molecular analysis with DNA methylation profiling is critical for diagnosis and management.

Keywords: Imaging findings; Pediatric tumors; Pineoblastoma; RB1 subgroup; Retinoblastoma.