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Table 1 Summary of radiologic findings and differential diagnosis

From: Masses of developmental and genetic origin affecting the paediatric craniofacial skeleton

 

US

RX

CT/CBCT

MRI

FDG PET

Differential diagnosis

Fibrous dysplasia (FD)

(Not indicated)

Expanded, thickened bone with ground-glass density

Occasionally areas of sclerosis or lucency

Expansile bone lesion in the medullary space with variable attenuation: sclerotic FD (ground-glass density), pagetoid FD (mixed radiopacity and radiolucency), cystic FD (centrally lucent lesions with thinned but sclerotic borders)

Low signal on T1 in ossified ± fibrous portions

Variable signal on T2. In the active phase, heterogeneous pattern

Usually, high ADC values on DWI

Fibrous components may enhance intensely

Variable FDG metabolism

Paget disease (adults)

Ossifying fibroma

Meningioma

Metastasis

Chondrosarcoma

Giant cell tumour

Cherubism

Submandibular lymph node enlargement may be present

Well-defined, bilateral, multilocular, expansile, radiolucent lesions of the jaws in children

Symmetrical enlargement of the mandible and maxilla

Teeth displacement, absence of dental follicles

Symmetrical, multilocular pseudocysts in the jaws, with few irregular bony septa, usually without other craniofacial involvement

Rounded scalloped lesion margins with marked bony expansion

Heterogeneous signal intensity

Signal intensity changes in areas that are apparently normal on radiographs or CT

(Not indicated)

Central giant cell granuloma

Noonan-like/multiple giant cell lesion syndrome

Hyperparathyroidism

Odontogenic keratocyst (OKC) in NBCCS

(Not indicated)

Multiple and expansile cystic masses of the jaws

Radiolucent with sclerotic rim

Unilocular or multilocular lesions

May displace developing teeth, resorb roots of erupted teeth, cause tooth extrusion

Rarely resorption of adjacent teeth

Corticated expansile cystic lesions with smooth or scalloped borders

Density varies with viscosity of contents

No detectable enhancement

Intermediate to high signal on T1 and heterogeneous signal on T2

May have low ADCs due to ortho-/parakeratin and/or haemorrhage

No solid enhancing tissue, thin or no enhancing rim

(Not indicated)

Periapical (radicular) cyst

Dentigerous (follicular) cyst

Ameloblastoma

Torus

(Not indicated)

Areas of increased bony density of variable size arising from the mid-portion of the hard palate (TP) or along the mandibular or maxilla margins (TM and TMax)

Often of fortuitous discovery

Typical localisation in oral cavity

Bone density of a non-infiltrating exophytic cortical bone lesion, without enhancement

Low signal intensity in T1 and T2

No soft tissue involvement and no enhancement

(Not indicated)

Osteoma

Dermoid and epidermoid cysts

Well demarcated avascular homogeneous mass in epidermoid type

Heterogeneous echostructure and minimal increase through transmission ± hyperechoic focus with posterior acoustical shadowing consistent with calcification in dermoid type

Pseudosolid appearance

(Not indicated)

Epidermoid: low-density, well-demarcated cystic mass with fluid density material inside the lesion

Dermoid: well-circumscribed cystic mass with fatty, fluid, calcified or mixed contents

Typical location, ovoid or tubular morphology

Depending on their location, DC may present as osteolytic lesions or may cause scalloping of the near bone

Epidermoid: homogeneous fluid signal (high signal on T2), diffuse high signal on T1 if high protein fluid. Typically restricted diffusion on DWI

Dermoid: heterogeneous high signal on T2 (intermediate signal if fat, focal areas of low signal if calcifications, complex fluid signal on T1). Fatty elements show focal or diffuse high signal on T1 and low signal if fat saturation is used. May have restricted diffusion on DWI. Thin rim enhancement or none

(Not indicated)

Depending on the location of DC:

Supraorbital region, floor of the mouth and cheek:

Thyroglossal duct cyst

Lymphatic malformation

Ranula

Abscess

Intraorbital:

Orbital infantile haemangioma

Orbital lymphatic malformation

Orbital venous malformation

Nose (see below)

Nasal dermoid sinus cyst (NDSC)

(See above)

No specific x-ray findings on the radiograph of the skull

Midline lesion anywhere from nasal tip to the anterior skull base at the foramen caecum

Fluid attenuation cyst and tract from nasal dorsum to skull base within nasal septum

Fat-containing mass (dermoid)

No specific enhancement

Bifid or deformed crista galli or cribriform plate with large foramen caecum

Morphology: ovoid mass ± tubular sinus tract

The lipomatous content of the NDSC appears hyperintense on T1 and hypointense on fat-suppressed images (dermoid)

Sagittal plane displays course of sinus tract from nasal dorsum to skull base

Restricted diffusion on DWI (epidermoid)

Rim enhancement or none

(Not indicated)

Nasal glioma

Fronto-ethmoidal cephalocele

Fatty marrow in crista galli

Non-ossified foramen caecum

Plexiform neurofibroma (PNF)

Lobular, serpiginous infiltrative soft tissue mass

Trophic changes and specific signs of bone involvement of the affected structures

Infiltrative trans-spatial appearance

Mild contrast enhancement

Target sign: central T2 hypointensity in the multilobulated hyperintense mass

Contrast enhancement of infiltrative solid mass (mild to moderate)

Hypermetabolism in sarcomatous transformation

Venous malformation

Lymphatic malformation

Sarcoma

Venous vascular malformation (VVM)

Variable size of multilobulated, solitary or multiple, spongy and compressible lesion with vascular channels

No arterial flow on colour Doppler

Hyperechoic foci with posterior acoustic shadowing consistent with phleboliths (if present)

Characteristic phleboliths

May show trophic changes of adjacent bones

Circumscribed or trans-spatial, lobulated soft tissue mass, isodense to muscle, with rounded calcifications (phleboliths), often drained by enlarged veins

Variable contrast enhancement: patchy and delayed or homogeneous and intense

No enlarged feeding arteries

Bone remodelling of the adjacent bone

Multilobulated mass with variable signal intensity on T1

Cyst-like appearance of large vascular channels, hyperintense on T2

Smaller vascular channels appear more solid and with intermediate signal intensity

Vascular signal voids on T2 due to enlarged dysplastic draining veins

Phleboliths appear as rounded or oval signal voids

Contrast enhancement is variable, may be mild to intense, delayed, heterogeneous or homogeneous

Lymphatic component of VM do not enhance

(Not indicated)

Arteriovenous malformation

Lymphatic malformation

Infantile haemangioma

Dermoid and epidermoid cyst

Lymphatic malformation (LM)

Multicystic paediatric soft tissue mass with fluid–fluid levels

Macrocystic LM (> 1 cm): soft, compressible anechoic cystic mass, usually with thin internal septations

High echogenicity if haemorrhage or proteinaceous fluid

Microcystic LM (< 1 cm): infiltrative solid-appearing mass of subcutaneous soft tissue, mildly hypo- or hyperechoic

(Not indicated)

Multilocular, fluid-attenuation mass, typically uniform, may contain foci of high attenuation due to haemorrhage or protein or low attenuation due to fat or lymph components

Subtle fluid–fluid levels of blood products

Contrast enhancement of septations in macrocystic LM

Largely bright fluid signal intensity mass with hypointense septa on T2

Fluid–fluid levels due to haemorrhage

Bright signal intensity on T1 due to haemorrhage, protein, fat and lymph components

Thin rim/septal contrast enhancement of macrocystic lesion. Confluent enhancement of infiltrating tissue in microcystic LM

No high-flow vessels intrinsic to lesion

(Not indicated)

Venous malformation

Infantile haemangioma

Soft tissue sarcoma

Soft tissue infection

Cephalocele

Obstetrical US: soft tissue mass through osseous defect

Fronto-ethmoidal: midline frontal, intranasal or medial orbital bony defect

Heterogeneous, mixed-density mass variable amounts of CSF and brain parenchyma, extending through bony defect

Intrathecal contrast fills subarachnoid space and surrounds soft tissue extending through bony defect (used only when MRI and CT still equivocal)

CT cisternography may be useful in localising CSF leak, especially if CSF rhinorrhoea or otorrhoea is present

Fronto-ethmoidal: crista galli may be bifid or absent. Deficient or absent cribriform plate

Skull base: depicts osseous defect in skull base

Temporal bone: focal bone defect in tegmen tympani or mastoid

Petrous apex: unilateral or bilateral smooth expansile petrous apex lesion due to herniation of posterolateral wall of Meckel cave

Enlarged petrous apex porus trigeminal notch

Soft tissue mass isointense to grey matter on T1

Hyperintense signal of CSF surrounds herniated soft tissue parenchyma on T2

Tissue may show hyperintense signal due to gliosis

Mass showing contiguity with intracranial brain parenchyma and CSF

No abnormal contrast enhancement or mild rim enhancement is noted within soft tissue

Meninges may enhance in case of infection or inflammation

(Not indicated)

Depending on the location of cephalocele:

Fronto-ethmoidal (frontonasal, nasoethmoidal, naso-orbital type) and skull base (nasopharyngeal, spheno-orbital and sphenomaxillary type):

Nasal glioma

Orbital dermoid and epidermoid

Nasal dermal sinus

Nasolacrimal duct mucocele

Teratoma

Temporal bone:

Cholesteatoma with tegmen dehiscence

Middle ear cholesterol granuloma

Temporal bone arachnoid granulation

Petrous apex:

Petrous apex cholesterol granuloma

Petrous apex congenital cholesteatoma

Petrous apex mucocele