Retinoblastoma

Case contribution: Dr Radhiana Hassan

Clinical:

  • A 2 years old boy
  • Right eye leukocoria since 6 months old
  • Examination shows absent reflex in right eye
  • Anterior segment leukocoria with vascularization
  • B scan shows lobulated lesion in right eye

    MRI brain in axial plane, T1, T2 and T1+Gadolinium sequences

MRI findings:

  • Lobulated right retinal mass (yellow arrows)
  • Measures 3.6 cm in widest length, 0.9 cm in thickness
  • Intermediate signal on T1, low signal on T2
  • Restricted diffusion on dwi and blooming artifact also seen (images not shown)
  • Mild contrast enhancement post contrast

Diagnosis: Retinoblastoma (HPE proven)

Discussion:

  • Retinoblastoma is the most common pediatric intra-ocular tumour.
  • The average age at diagnosis is 18 months.
  • About 80% of cases occurring before the age of 3–4 years old.
  • It is a highly malignant tumour of the primitive neural retina.
  • About 30% are bilateral.
  • Lesions may be synchronous, metachronous, unifocal or multifocal.
  • It may be endophytic, exophytic or diffusely infiltrating.
  • Ultrasound shows a solid echogenic mass with high echogenic foci of calcifications.
  • At T1-weighted MR imaging, retinoblastoma shows intermediate signal intensity, slightly hyperintense to the vitreous. The vitreous may be abnormally bright on T1-weighted images because of increased globulin content and a decreased ratio of albumin to globulin that occurs with malignancy.
  • At T2-weighted MR imaging, the tumour is usually dark compared with the vitreous. The partially calcified areas may appear as hypointense foci within the tumour
  • The tumour shows moderate to marked enhancement.
  • The tumour shows restricted diffusion on diffusion weighted imaging

References/Further reading:

  1. Guidelines for imaging retinoblastoma: Imaging principles and MRI standardization. Paediatric Radiology 2012; available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256324
  2. Retinoblastoma at https://radiopaedia.org/articles/retinoblastoma
Author: radhianahassan