Head and neck

Question 1

Most common childhood soft tissue sarcoma?

Answer 1

Rhabdomyosarcoma.

Question 2

Most common benign orbital mass in childhood?

Answer 2

Desmoid.

Question 3

Most common extra-ocular orbital malignancy in children?

Answer 3

Rhabdomyosarcoma.

Question 4

Age of presentation or rhabdomyoscaroma?

Answer 4

Most of them (70%) <12 years.
Les frequently (40%) < 5 years.

Question 5

Describe histological subtypes of rhabdomyosarcomas

Answer 5

4 histological subtypes:
-Embryonal RMS (50%): most common, young children (mutation in 11p15locus). 70-90% affecting H&N or genitourinary tract.
(BOTRYOIDES variant: typically in 2-5 years of age, develops in the walls of hollow, mucosal lined structures such as nasopharynx, common bile duct, bladder and vagina. Has the most favourable prognosis)
-Alveolar RMS (20%): 2nd most common; 15-25 years, adolescence. Most common in extremities and trunk. 50% have FOX01 to PAX3 (or PAX7) gene fusion (better prognosis)
-Pleomorphic RMS (20%): Least common; 40-60 years. Adults. Extremities (rarely in H&N). Often fatal.
-Spindele cell/sclerosing (10%): affects all ages.

Question 6

Epidemiology of rhabdomyosarcoma

Answer 6

-Most common childhood soft tissue sarcoma (most common extra ocular orbital malignancy)
-Age presentation < 12 years (70%) / < 5 years (40%).
-Most common in Caucasian.
-40-50% occur in H&N (most commonly in orbit, sinus (parameningeal sites, and other)), genitourinary tract (25%), extremities (15%), other (10%)

Question 7

Frequent sites of affection of rhabdomyosarcoma

Answer 7

40-50% H&N
25% genitourinary (bladder, vagina, prostate)
15% extremity
10% other (common bile duct)

Question 8

Syndromes and conditions associated with rhabdomyosarcoma

Answer 8

Increase incidence of RMS in:
Noonan syndrome,
neurofibromatosis type 1,
Li-Fraumeni,
Beckwith-Wiedemann,
hereditary retinoblastoma.

May occur as radiotion-induced 2nd primary neoplasm.

Question 9

Complications of rhabdomyosarcoma

Answer 9

Intracranial extension (up to 50%)
Perineural spread
Metastasis (20%) to lungs and bone marrow.

Question 10

Diagnosis clue for rhabdomyosarcoma

Answer 10

Clue: invasive soft tissue mass with variable enhancement.
* CT: Invasive soft tissue mass with variable enhancement
Osseous erosion common but not seen in all cases (in 20%)
* MR: T2FS, Stir: Isointense T1, hyperintense T2 signal relative to muscle (Not “fluid bright” unless necrotic/cystic components)
T1 C+ FS: Variable contrast enhancement, often mild to moderate (Diffuse, intense enhancement atypical)
Often restricts diffusion
* PET/CT: hypermetabolic (improve staging and posttreatment evaluation).

Question 11

Most common primary intraocular neoplasm in childhood

Answer 11

Retinoblastoma

Question 12

Path behind retinoblastoma (genetics)

Answer 12

Mutation of the retinoblastoma gene (tumor suppressor gene in Ch13)(lack of both alleles)

Question 13

Describe incidence of bilateral vs unilateral retinoblastoma and genetic background

Answer 13

Unilateral = 60%. Sporadic somatic mutation of both alleles of RB1.
Bilateral= 40%. AD, involves a hereditary germinal mutation of RB1 + sporadic mutation of the other copy.

Question 14

CT appearance of retinoblastoma

Answer 14

> 90% presents calcium deposits within irregularly thickened retina.
Heterogeneous post contrast enhancement.

Question 15

MR appearance of retinoblastoma

Answer 15

T1 slightly hyper to vitreous
T2 slightly hypo to vitreous.
Post con: heterogeneous enhancement

Question 16

Associations when bilateral retinoblastoma

Answer 16

-Trilateral: bilateral RB +mid line intracranial tumor (pineal tumor)
-Quadrilateral: bilateral RB + mid line intracranial tumor +/- suprasellar tumor
-All of them at reisk of other germ line malignancies: sarcoma, melanoma, CNS tumor, epithelial (lung, bladder, breast)

Question 17

Growth morphology of retinoblastoma

Answer 17

-Endophytic 45%, inwards protrusion into vitreous
-Exophytic, 45%, outwards into subretinal space, associated with retinal detachment and subretinal exudate.
-Mixed 10%
-Diffused infiltrating form (rare), plaque like growth, often no Ca+

Question 18

Invasion rout of retinoblastomas

Answer 18

Extraocular extension in < 10% of cases :
-choroidal invasion: localized thickened and heterogeneous contrast enhancement near tumor
-Scleral invasion: interruption in thin, hypointense zone surrounding enhancing choroid.
-Optic nerve invasion: thickening of optic disk (prelaminar), enhancement of nerve (post laminar)

Question 19

Diagnostic methods of retinoblastoma

Answer 19

-Opthalmoscopy
-Ultrasound (A and B scan)
-CT (Ca+)
-MR (mapping and prognostication)

Question 20

Differential diagnosis of retinoblastoma

Answer 20

-Persistent hyperplastic primary vitreous
-Coat’s disease
-Toxocariasis
-Retinopathy of prematurity
-Coloboma
-Other causes of leucocoria (retinal detachment)

Question 21

Most common retinal pathologies

Answer 21

Retinoblastoma (childhood)
Hemangioblastoma (adult)
Detachment (diabetic retinopathy)

Question 22

Most common choroid pathologies

Answer 22

Melanoma
Metastases (since it is the most vascular structure in the eye)
Detachment.

Question 23

Most common sclera pathologies

Answer 23

Infection
Pseudotumour
Detachment

Question 24

Path of Persistent hyperplastic primary vitrous

Answer 24

Congenital developmental malformation due to incomplete/failure of hyaloid regression, causing remnant to persist in Cloquet canal (should involute by 8th months)
Most cases isolated and sporadic.
Dominance and recessive forms described.

Question 25

Associations and complications of Persistent hyperplastic primary vitrous

Answer 25

-Usually isolated (90%)
-When bilateral, could be associated with systemic or syndromic conditions (Norrie, Walker Warburg, T13), perinatal infection (congenital cMV and rubella) methabolic (maternal cocaine abuse)

-Complications: retinal detachment, glaucoma .

Question 26

Morphology of Persistent hyperplastic primary vitous

Answer 26

-Retrolental soft tissue and stalk with martini glass shape of enhancing soft tissue (triangular retrolental vascular tissue + central stalk of hyaloid remnant)
-Location: 50-80% mixed anterior and posterior/ 15-25% isolated posterior form / 5-20% isolated anterior form/
-Unilateral (90%) > bilateral (10%)

Question 27

Diagnostic modalities for PHPV

Answer 27

CT: Small globe, linear retrolental density &/or vitreous hemorrhage, retinal detachment. Calcification rare

MR: -Retrolental martini glass-shaped enhancing soft tissue.
-Small globe, vitreous abnormally hyperintense on both T1WI and T2WI
-Hemorrhage and layering debris in vitreous &/or retinal detachment common (signal depends on age of blood)

US: -Lens displacement, hyperechoic retrolental stalk
- Thickened hyaloid seen as double line at pars plana

Question 28

What is coloboma?
Associations?
Diagnostic features?
Most important Diferential diagnosis?

Answer 28

-Congenital defect caused by failure of closure/fusion of fetal optic fissure. Appears as outpouching of the optic tissue (retina, choroid, sclera,iris). Most frequently INFERO NASAL location.

-If bilateral, suspect syndromic associations: CHARGE, T13, T18, VACTER etc)

-Dx: Isodense/isointense to vitreous on CT and MR.
Sclera enhances post contrast.
Ca+ rare (only when chronic, and at margins)

-DD: Staphyloma: focal outpouching due to thinning and stretching of scleral-uveal (outer) layer of globe.
Posterior types are the most common, off centered more TEMPORAL to optic nerve.

Question 29

Causes of leukocoria

Answer 29

-Neoplastic
Retinoblastoma (<3 years, Ca+)
Ocular melanoma
-Acquired:
Retinal detachment
Retinoplasty of prematurity
Coloboma
-Infection: Toxocariasis
-Congenital:
Congenital cataract
Persistent Hyperplastic Primary Vitrous
Coat’s disease

Question 30

Retinal detachment
-Cause
-Clinical presentation
-Physiopath
-Diagnostic features

Answer 30

-Cause: Trauma, Traction (DM), exudative (neoplasia)

-Clinical presentation: Reduced visual acuity, floaters, flashes, visual field loss

-Physiopath: Separation of the inner neurosensory retina from the outer pigmented epithelial layer. Fluid in subretinal space.

-Dx features:
Detached retina demonstrates aftermovements
Limited anteriorly by ora serrata
Converges posteriorly on optic disc

Question 31

Choroidal detachment:
-Cause
-Clinical presentation
-Physiopath
-Diagnostic features

Answer 31

-Cause: Increased intraocular pressure (transudative effusion due to trauma, exudative effusion due to infection or inflammation), haemorrhage, other (valsalva, hypertension, neoplasm, caroticocavernous fistula)

-Clinical presentation: Dull to severe pain

-Physiopath: detachment of the choroid from the underlying sclera. Fluid in suprachoroidal space

-Dx features:
NO aftermovements of the detached membrane
NOT limited anteriorly by ora serrata
Diverges from optic disc posteriorly

Question 32

Lens dislocation:
-Cause
-Clinical presentation
-Physiopath
-Diagnostic features

Answer 32

Cause:
-Trauma is the most common cause.
-Non traumatic: Marfan syndrome (typically upwards and out), homocystinuria (typically downwards), Weil-Marchesani syndrome, Ehlers-Danlos. Hereditary. Infective (syphilis)

Clinical presentation: History of trauma, or reduced visual acuity

Physiopath: Subluxation or dislocation of the lens.

Dx features:
-Subluxation: Unilateral deviation of lens margin posteriorly into vitreous body. Contralateral margin fixed adjacent to iris.
-Complete dislocation: lens in dependent position in the vitreous.
Free mobility with eye movements.

Question 33

Subtypes of Optic Pathway Glioma
Histopath
Epidemio
Dx pearls

Answer 33

Most common in childhood (>90%) less than 20yo. (most common onset 10yo)

-Childhood syndromic to NF1 (30-40%)
Low grade gliomas (pilocytic astrocytoma/ fibrillary astrocytoma).
Irregular, buckling and kinking.
Anterior pathways.
T1 peripheral hyperintensity (perinerual arachnoid gliomatosis)

-Childhood sporadic
Low grade gliomas (pilocytic astrocytoma/ fibrillary astrocytoma)
Fusiform. Cystic changes.
Posterior pathways, including chiasm.

-Adult type.
High grade gliomas (GBM)
ON and sheath, posterior spread.

Question 34

Main differential diagnosis with optic sheath meningioma?

Answer 34

Optic Pathway Glioma:
-Variable enhancement
-no Ca+
-Irregular ON itself

Opthic sheath meningioma:
-Uniform enhancement
-Usually Ca+ in 1/3 to 1/2 of the cases.
-Mass is surrounding ON.
-Characteristic perioptic cyst (entrapped CNS)