7th Jun 2021

ICRI CASE OF THE WEEK

Contributors : Dr Mankirat Singh, Dr Jyoti Kumar, Dr Rajat Jain
Department of Radiology, MAMC, New Delhi

Copyright of the Case belongs to : Dr Jyoti Kumar
Professor, Department of Radiology
MAMC, New Delhi

Clinical Details

A 2 year old male child
Mother noticed a white spot in the window of the right eye for 3 months
Gradual protrusion of right eye and misaligned eyes
Child was referred for MRI evaluation

Describe the marked findings. What is your diagnosis?

Retinoblastoma typically demonstrates Low signal intensity than vitreous on T2-
slightly higher signal intensity than vitreous weighted images ( red and black arrows)

on T1W (red and green arrows)

Represents vitreous hemorrhage anterior
to the lesion

Contrast enhanced axial and coronal images demonstrate marked contrast enhancement
NOTE- Right Optic nerve thickening and intracranial extension via the optic foramen

Few tiny areas of blooming noted within Reduced diffusion on DWI suggestive of
the lesion on SWI s/o Calcification high tumor cellularity

Intracranial extension of the tumor

1. What does this structure represent?

2. What is the ICRB stage of the tumor?

3. What are the poor prognostic features on MRI? 4. What are the second primary tumors that can develop in
Hereditary cases?

1. What does this structure represent?
CHOROID layer

2. What is the ICRB stage of the tumor?
Stage F (EXTRASCLERAL)

3. What are the poor prognostic features on MRI? 4. What are the second primary tumors that can develop in
Hereditary cases?
• Choroid invasion
• Optic nerve invasion Patients with germline disease have increased risk for
• Extraocular tumor extension developing osteosarcoma and soft tissue sarcoma,
• Intracranial disease melanoma, and malignancies of the brain later in life

Retinoblastoma

 Most common intraocular tumor of childhood

 Most cases are diagnosed within first five years of life, with a median age of
diagnosis of 18-24 month

 There is mutation of Rb1 gene on chromosome 13.

SPORADIC (60%) HEREDITARY (40%)

Increased risk for developing other malignancies

later in life
 osteosarcoma
 soft tissue sarcoma
 melanoma
 malignancies of the brain

CLASSIFICATION

UNILATERAL BILATERAL TRILATERAL QUADRILATERAL
One globe (75%) Both globe (25%)
Both globes Both globes
+ +

Pineal / Suprasellar lesion Pineal
+
(5% of bilateral tumors)
Suprasellar

MRI can provide important diagnostic and prognostic information in retinoblastoma and
is vital for screening for trilateral retinoblastoma

Grouping System for the International Classification of Retinoblastoma (ICRB)

Group Description Features
Group A Small
• 3 mm in any diameter
Group B Large • located >3 mm from the foveola and >1.5 mm from the optic disc
• confined to the retina with no vitreous seeding
Group C Local dissemination
Group D Diffuse • Macular or juxtapapillary location with no dissemination (subretinal
fluid extends <3 mm from tumor)
Group E Unsalvageable or
extensive • confined to the retina with no vitreous seeding

Group F Extrascleral Discrete; vitreous or subretinal seeding extending <3 mm from tumor

• Tumor is massive or diffuse with diffuse or greasy vitreous seeding or fine
subretinal seeds;

• avascular plaques or exophytic disease

One or more of the following poor prognostic factors:
• Neovascular glaucoma
• Intraocular or corneal hemorrhage,
• Tumor contact with the lens,
• Tumor in the anterior segment,
• Diffuse infiltrating retinoblastoma

Extrascleral spread to the optic nerve, orbit, or brain; distant metastases

Need for Imaging

 Diagnosis is usually established on the basis of fundoscopy (under general
anesthesia) and USG

 CT had been used historically to detect tumor calcification

 Because of potential increased risk for second cancers with ionizing radiation
exposure, especially in germline retinoblastoma, CT is avoided

 High-resolution MRI has emerged as the most important imaging modality for
pretreatment assessment

Poor prognostic features of Choroidal invasion and Optic nerve extension cannot be
reliably detected on clinical examination, therefore MR imaging of extraocular disease
and intracranial tumor is crucial

Role of MRI

Intraocular RB

 RD and subretinal seeding
 Choroidal Invasion
 Scleral and extra-scleral invasion
 Signs of increased intraocular pressure (Reduced anterior chamber depth, increased size of the globe,

globe deformation )

Extraocular RB and CNS involvement

 Post-laminar optic nerve or optic nerve meningeal sheath invasion
 Intra cranial PNET (trilateral RB)
 Leptomeningeal spread
 Congenital malformations (13q deletion syndrome)

MR imaging of the entire neuraxis should be performed to evaluate for leptomeningeal enhancement in patients with
extraocular extension of a retinoblastoma

Surveillance for second primary malignancies is not yet supported by strong evidence or broad consensus, though some
suggest there may be a role for annual screening by whole-body MRI (Friedman et al., 2014; Kamihara et al., 2017)

Imaging Guidelines

 General anaesthesia
 Orbits

-1.5 T & surface coil / 3T & head coil
-SW = 2 mm, Pixel < 0.5 x 0.5 mm
-T2 (SE, CISS)
-T1 SE before / after Gd (+ FS, -FS)
-Axial & sagittal

 Brain

-T2 axial or sagittal
-T1 Gad

de Graaf P et al. Guidelines for imaging retinoblastoma. Ped Rad 2012

Differential Diagnosis

Although leukocoria is suspicious for retinoblastoma, other disease processes may also cause leukocoria-

COATS Disease

Characterized by retinal telangiectasia and retinal exudation.
 Absence of calcification.
 Lack of enhancement at contrast enhanced MR imaging.

PHPV

Persistent Hyperplastic Primary Vitreous.
 Failure of primary vitreous to regress during embryonal development
 Retrolental mass which shows enhancement & extends into Hyaloid (cloquet) canal.

RETINAL ASTROCYTIC HAMARTOMA

 Predominantly associated with tuberous sclerosis
 May be associated with an exudative retinal detachment, hemorrhage and calcification.
 Unlike RB, it rarely grows in size and if it does, only modestly

Teaching Points

 Patients with the heritable form of retinoblastoma have a higher propensity for
bilateral disease and a second primary malignancy

 MRI can provide important diagnostic and prognostic information in retinoblastoma
and is vital for screening for trilateral retinoblastoma.

 Choroidal invasion and optic nerve involvement are poor prognostic markers for
disease dissemination.

 Choroidal invasion & optic nerve extension cannot be reliably detected on clinical
examination, therefore MR imaging of extraocular disease and intracranial tumor is
crucial

 MR imaging of the entire neuraxis should be performed to evaluate for leptomeningeal
enhancement in patients with extraocular extension of a retinoblastoma

THANK YOU