Head and Neck 2 Flashcards
Anterior skull base Mucocele
- expanded sinuse from chronic obstruction
- variable signal depending on protein content of secretions
- No solid enhancement
- can see mucosal enhancement around the margins
- Non-agressive with bone remoddeling
- MRI highly accurate for distinguishing higher density/proteinaceaus secreations that are equivocal on CT from Solid masses
- DDX
- mucus retention cyst
- does not completely fill the sinus
- no bony expansion
- paranasal sinus carcinoma (generally isointense or of intermediate intensity on MR imaging sequences) 5
- aspergillus sinusitis
- dermoid cyst
- osteoma (rare) 6
- mucus retention cyst
PNS can be antegrade and retrograde
True or false?
true.
What is PHPV associated with?
- Other ocular dysplasias
- Norrie disease
- seizures
- deafness
- low IQ
Rad Features of Optic Nerve Meningioma
- Mass
- tubular 65%
- Exophytic/eccentric 25%
- Fusiform/surrounding the optic nerve 10%
- Calcification common
- Enhancement
- intense contrast enhancement
- Linear bands of enhancement (nerve within tumour) Tram track sign
- Sphenoid bone +/- optical canal hyperostosis in advanced tumours
Clinical symptoms of Optic nerve glioma
- Loss of vision
- proptosis (in bulky tumours)
- Occur most commonly in the 1st decade of life
- May be bilateral in NF1
Orbital hemangiopericytoma
Orbital hemangiopericytoma
- uncommon
- slow growing vascular neoplasm
- can be benign or malignant
- well-circumscribed or invasive when high grade
- may remodel or erode bone
- avidly enhancing
- flow voids common on T2
Buphthalmos
Buphthalmos
Buphthalmos:
- congenital glaucoma, anterior ocular chamber drainage problem
- enlarged globe
- increased depth of anterior chamber
Causes of Optic Neuritis
- Idiopathic
- MS
- Neuromyelitis Optica (Devic syndrome)
- Acute demyelinating encephalomyelitis (ADEM)
- Paediatric Optic Neuritis (may follow viral illness or vaccination, ADEM)
- Anterior skull base Meningocele/encephalocele
- extension of meninges +/- brain parenchyma through skull base defect into nasal cavity or ethmoidal labyrinth.
- CT can show bone defect
- high res MRI for confirmation
- Heavily T2 high rest sequences can be helpful for clear demonstration of extension of meninges and or brain through defect.
- https://thejns.org/focus/view/journals/neurosurg-focus/32/6/2012.3.focus1267.xml
what does ocular melanoma arise from?
- arises from pigmented choroidal layer
- retinal detachment is common
Ecchordosis Physaliphora
Ecchordosis Physaliphora
Cystic lesion in the prepontine cistern without enhancement or restricted diffusion extending into bone.
Absence of enhancement or restricted diffusion together with non-aggressive bony margins in this location is typical of a retroclival ecchordosis physaliphora, a notochord remnant.
Ecchordosis physaliphora is a congenital benign hamartomatous lesion derived from notochord remnants, usually located in the retroclival prepontine region, but can be found anywhere from the skull base to the sacrum.
Terminology
There has been some controversy as to whether intradural chordoma and large ecchordosis physaliphora are different entities. Some authors (such as Wolfe et al.) proposed the name ‘intradural chordoma’ for all intradural notochordal remnant lesions 8. Others (such as Rodriguez et al.) proposed that all intradural notochordal remnant lesions should be called ecchordosis physaliphora, until chordoma are pathologically proven to arise from the intradural compartment 9. However, they are currently considered distinct pathologies with a common origin.
Clinical presentation
Unlike chordomas which are often symptomatic due to brainstem or cranial nerve compression, patients with ecchordosis physaliphora are usually asymptomatic. They are found in ~2% of autopsies 1.
Pathology
Ecchordosis physaliphora arise from remaining notochord cells along the axis of the spine after embryogenesis. Unfortunately, ecchordosis physaliphora and chordoma are histologically indistinguishable, other than by examining the margins, the latter demonstrating infiltrative growth.
Central skull base Aneurysms
Central skull base Aneurysms
- Cavernous or other ICA aneurysms
- Rounded ‘mass’
- low signal
- flow void on MRI MUST RECOGNISE
- Pulsation artifact in phase enconding direction
- CT or MRI angio to confirm
Rhabdomyosarcoma
Rhabdomyosarcoma
- Most common malignant orbital tumour in childhood.
- mean age 7 years
- Large aggressive soft tissue mass
- intraconal or extraconal
- mets to lung and cervical nodes
- Rhabdomyosarcomas of the orbit account for approximately 10-20% of all rhabdomyosarcomas and are usually found in children.
- Epidemiology
- As with other locations, rhabdomyosarcomas in the orbit are overrepresented in males, and in Caucasians.
- They typically occur in children below the age of 15 years.
- Clinical presentation
- Clinical presentation is typically with a rapidly enlarging mass, often in the upper inner quadrant 1.
- It is usually painless but causes proptosis and diplopia.
- Often the mass invades the eyelid causing marked oedema 1.
- Pathology
- The vast majority of orbital rhabdomyosarcomas are of the embryonal subtype 1,3.
- Contrary to early belief, these tumours do not arise from the extraocular muscles, but rather develop from primitive mesenchymal cells that go on to differentiate into striated muscle cells 3.
- The vast majority of orbital rhabdomyosarcomas are of the embryonal subtype 1,3.
- Histologic subtypes:
- embryonal
- alveolar
- mixed
- Radiographic features
- CT and MRI are the modalities of choice for assessment of these masses, and to delineate adjacent structures.
- It is important to report the location of the tumour epicentre as there is a correlation between location and histology:
- embryonal subtype more frequently arises in the superior orbit, whereas
- alveolar subtype is more common in the interior orbit 3.
What are the radiographic findings of ocular melanoma?
- Thickening or irregularity of choroid
- localised
- polypoid
- flat
- exophytic biconvex mass lesion
- usually initlateral posterior location
- retinal detachment common
- contrast enhancement
- MRI
- T1 bright
- T1 low
*
WHICH nerves does PNS most often occur?
PNS (perineural Spread) most commonly occurs along CN V and VIII branches
Complications of Optic Neuritis
40-60% of patients ultimately develop MS
70-90% of MS patients develop optic neuritis
- Meningioma
- occasionally lesions can be infiltrative, extend to extracranial spaces such as PPF and infratemporal fossa or have intraosseous component
Figure 2: Medial sphenoid wing meningiomas can present different set of technical challenges based on their involvement of the medial neurovascular structures and the encasement of the carotid artery’s perforating vessels. A medial sphenoid wing meningioma with minimal medial extension is shown (upper images). The Sylvian middle cerebral artery branches drape over the superior pole of the tumor. A more true medial sphenoid wing/clinoidal meningioma with significant medial extension and encasement of the ICA is also included (lower images).
Orbital Infantile Hemangioma Associated syndrome
PHACES syndrome
Posterior fossa malformation
Hemangioma
Arterial anomalies
coarct/cardiac anomalies
Eye anomalies
Sternal clefting/supraumbilical raphe
Sinonasal melanoma
- Sinonasal mucosal melanoma (SNMM) is a very rare and unique subtype of malignant melanoma.
- ON MRI: lesions may have intrinsically high signal on T1 and low signal on T2 - paramagnetic properties of melanin
-
Epidemiology
- SNMMs account for ~1% of malignant melanomas and <4% of head and neck cancers 1,2.
- They affect older patients (60-90 years old) 2.
- There is a higher incidence in Japan 5.
-
Clinical presentation
- Headache and visual symptoms are common.
-
Pathology
- Typically SNMMs are an expansile mass centred within the nasal cavity (more common) or the paranasal sinuses.
- Invasion is common, in particular to the orbits, base of the skull, intracranially, or nasopharynx.
- Hepatic metastases are common 4.
-
Staging
- Mucosal melanoma of the head and neck, including sinonasal mucosal melanoma, is staged according to the American Joint Committee on Cancer TNM system.
-
Radiographic features
- Radiographic features of SNMM are variable, especially on MRI, due to varying amounts of melanin, with up to one-third of cases being amelanotic 3.
-
CT
- polypoid or mass-like
- bony remodelling +/- erosion commonly present
- strongly contrast enhancing 5
-
MRISignal characteristics
-
T1: homogeneous T1 signal
- high T1 signal may be seen secondary to haemorrhage or melanin 5
- T2: low signal
- T1C+: moderate homogeneous or heterogeneous enhancement
- Metastases return the same signal characteristics as the primary lesion.
-
T1: homogeneous T1 signal
-
Treatment and prognosis
- SNMM is aggressive and carries a poor prognosis with a five-year survival rate of ~30% 3.
-
Differential diagnosis
- As a general differential in the sinonasal region consider other tumours such as:
- sinonasal undifferentiated carcinoma
- As a broader differential in the nasopharyngeal region, consider other nasopharyngeal tumours such as:
- As a general differential in the sinonasal region consider other tumours such as:
Central skull base Basal cephalocele
Central skull base Basal cephalocele
FIGURE 31-5 Basal encephalocele.A, A sagittal T1-weighted image shows callosal agenesis with a tiny lipoma (arrow). A large defect in the basisphenoid is seen. Note the apparent absence of the pituitary, floor of the third ventricle, and optic pathways. B, A high-resolution sagittal T2-weighted image shows the pituitary-hypothalamic structures (arrow) and optic pathways are contained within the encephalocele.
Anterior skull base Fibrous dysplasia
Anterior skull base Fibrous dysplasia
- expansile developmental bone lesion
- classically ground glass matrix
- varies depending on amount of firbous and ossified components.
- enhancing lesion can be deceptively aggressive on MRI (suspect if very low signal on T1 and T2
- obtain CT to demonstrate typical characteristics
Central skull base Persistent craniopharyngeal canal
Central skull base Persistent craniopharyngeal canal
- developmental anomaly resulting in a persistent tract from nasopharynx to pituitary fossa
- a smoothly marginated midline canal between presphenoid and basisphenoid
- typically incidental finding but may be a/w pituitary abnormalities, cephaloceles, midline craniofacial anomalies or rarely even tumours arising from tissue within the canal
Hemangiopericytoma of the anterior skull base
- hypervascular lesion with aggressive growth pattern
- dural based mas that may have internal flow voids
- intensely enhancing
- The magnetic resonance imaging (MRI) with contrast (A) sagittal (B) axial, and (C) coronal views depict a large contrast-enhancing mass arising from the olfactory groove, D: the MRI T2 weighted image demonstrates corkscrew type flow voids (white arrow), which are consistent with a highly vascular neoplasm.
- https://www.cureus.com/articles/9578-hemangiopericytoma-in-the-olfactory-groove-a-rare-and-unusual-presentation
What is the pathophysiology of Retrolental Fibroplasia?
what is the disease a/w?
- AKA Retinopathy of prematurity
- toxic retinopathy caused by oxygen treatment
- eg for Hyaline membrane disease
- A retinal vasoconstriction leads to neovascularisation and fibrovascular proliferation of the posterior vitreous and retina
- typically bilateral
- retinal detachement is common
- may be a/w
- hemorrhage
- calcs are rare except in advanced stages
Skull base chondrosarcoma
- Skull base chondrosarcoma
Chondrosarcoma
- arises in skull base fissures and synchondroses, most commonly petroocipital fissure.
- typically eccentric, incontraindication to chordoma
- Chondroid ring and arc like calcificaiton on CT
- heterogenously enhancing with high T2 signal with scattered hypointense foci on MRI
A very large mass, which has destroyed the left inferolateral aspect of the clivus, extends laterally through the floor of the left middle cranial fossa as far as its lateral wall. It extends inferiorly through the destroyed floor into the infra temporal fossa and posteriorly impinges upon the pons immediately to the left of midline. It contacts the left side of the basilar artery, but does not appear to encase it. The left internal carotid artery is markedly displaced laterally, almost to the lateral wall of the left middle cranial fossa. It is totally encased by the tumour as it emerges from carotid canal, but remains patent. Posterolaterally it has invaded through the destroyed petrous bone to abut the left cerebellar hemisphere. It occupies the jugular bulb and abuts the left internal auditory meatus on three sides.
Conclusion : Very large extension of left sided “clival chordoma” to almost entirely occupy the anterior aspect of the left middle cranial fossa, a small portion of the posterior fossa and the upper portion of the left infratemporal fossa.
Case Discussion
Pathology report on repeat surgery.
The sections show a moderately cellular tumour with a lobulated architecture. There are aggregates of epithelioid cells in blue-tinged chondroid-like stroma. The tumour cells have mildly enlarged and hyperchromatic nuclei, angulated nuclear contour, small nucleoli and small to moderate amounts of clear vacuolated to eosinophilic cytoplasm. No mitoses or necrosis is seen. Sections of the bone show tumour infiltrating into the medullary spaces. The tumour cells are S-100 positive. There is focal staining for M2A. EMA staining is equivocal. CAM5.2, AE1/3, CK19 and CEA are negative.
Comment: The previous biopsy has been reviewed. It showed similar morphology as compared to the current tumour with cellular nodules of cartilage, containing atypical chondrocytes. CAM5.2 was also negative. The overall features are those of grade 2 chondrosarcoma. Cytokeratin negativity excludes the diagnosis of chordoma .
The radiology has also been reviewed and chondrosarcoma is favoured over chordoma.
Final diagnosis : Skull base tumour: Recurrent grade II chondrosarcoma.
Caroticocavernous fistulas (CCF) represent abnormal communication between the carotid circulation and the cavernous sinus. They can be classified as direct or indirect which are separate conditions with different aetiologies.
Epidemiology
Direct caroticocavernous fistulas are often secondary to trauma, and as such the demographics reflect the distribution of head trauma, most commonly seen in young male patients. The presentation is acute and symptoms develop rapidly.
In contrast, indirect caroticocavernous fistulas have a predilection for the postmenopausal female patient and the onset of symptoms is often insidious.
Other conditions that predispose to increased risk include:
Ehlers-Danlos syndrome
fibromuscular dysplasia
Which cell types do optic nerve meningiomas arise from?
Optic nerve sheath meningiomas arise from arachnoid rests in meninges covering the optic nerve
What is the orbital septum?
- Fascia arising from the orbital rim periosteum
- attaches to outer margins of the bony orbit and deep tissues of the lids
- separates structures in the orbit from soft tissues in the face
- ie Post septal vs septal
Types of post septal orbital infection
- Infiltration of the extraconal, post septal fat
- Subperiosteal infiltrate or abscess
- lateral displacement of enlarged medial rectus muscle
- Stranding of retrobulbar fat if intraconal extension
- proptosis
- Evaluate paranasal sinuses for a potential source
- Bacertial infections can be complicated by cavernous sinus thrombosis
- mets Neoplasms of the central skull Base
- Mets:
- suspect in patient with known malignant neoplasm with new craniofacial pain or cranial neuropathy
- Lytic destructive lesion
- may have a/w soft tissue mass
- look for multiple lesions
What are poor prognostic factors for occular melanoma
- large tumour size
- lack of pigmentation is a/w aggressiveness
- infiltration of the angles, optic nerve, sclera, ciliary body
What is Coat’s disease?
- primary vascular abnormality
- AKA Exudative Retinitis
- Exudative Retinopathy
- cause of Leukokoria
- Causes lipoprotein accumulation in the retinal
- telangieactasia
- neovascularisation
- retinal detachement
- pseudoglioma
- Typcially occurs in the 1st decade
- M>F
- A/w
- VATER Syndrome
Central skull base Langerhans cell histiocytosis
Langerhans cell histiocytosis
- lytic enhancing lesion typically presenting in the first decade of life
- Case Discussion
Langerhans cell histiocytosis (LCH) is characterised by the proliferation of mononuclear cells resulting in granulomatous lesions. Patients may present with isolated or systemic disease 1.
Bone lesions are the most common manifestation of LCH radiologically occurring in around 80% of patients. Most commonly LCH affects flat bones with the skull being the most common site involved followed by mandible, ribs, pelvis and spine 2.
Skull involvement commonly reveals a well defined lytic “punched-out” appearance due to asymmetrical destruction of the inner and outer cortices on CT or x-ray. Magnetic resonance imaging reveals a soft tissue component commonly hyperintense on T2 weighted images, isointense of T1 weighted images and enhances post-contrast 2.
Ear involvement occurs in 15% of cases and may present with otorrhoea, mastoid swelling, external auditory canal (EAC) polyps, or cholesteatoma. Treatments include surgical or systemic options 1,3.
https://radiopaedia.org/cases/langerhans-cell-histiocytosis-of-the-mastoid
what is unique about breast mets to the orbit?
- breast mets to the orbit may have retractile firbotic stroma and paradoxically be a/w enopthalmos
- A) Clinical photograph of a 59-year-old female with enophthalmos of the left eye secondary to metastatic scirrhous carcinoma of the breast. (B) The CT scan demonstrates irregular opacification (metastatic disease with fibrosis) in the left posterior orbit (arrow) with resulting retraction of the globe.
Lacrimal Gland Adenocystic Carcinoma
Pic one tumour 2 years later
Pic two tumour 2 years earlier
Tumors of the lacrimal gland account for 10% of all space-occupying tumors of the orbit (1). Histologically, they are broadly characterized as epithelial and non-epithelial. The most common epithelial tumor is a benign pleomorphic adenoma, accounting for half of all epithelial tumors. The remaining half is malignant, with 20-30% identified as adenoid cystic carcinoma (ACC) (2). Overall, ACC accounts for 1.6% of all lacrimal gland tumors. Little is known regarding risk factors for development of ACC. Neither race nor geographic location contributes to risk and ACC is also equally prevalent among both genders (2). However, cigarette smoking and ionizing radiation have been reported as factors for corresponding similar carcinomas of the salivary glands (3).
ACC typically presents at a mean age of 50, although it is also found in children and the elderly (4). ACC can be slow growing, but with a more subacute worsening of symptoms (<1 year) than benign lesions of the lacrimal gland. Signs and symptoms include globe displacement, swelling/palpable mass, diplopia, and ptosis. The presentation may be subtle, and patients can often first present with only a complaint of pain. Up to 58-80% of patients with ACC complain of pain due to the tumor’s tendency toward perineural invasion, particularly along the trigeminal nerve (5). One study reported up to 72% of tumor specimens showed evidence of perineural involvement (6).
A definitive diagnosis is obtained through tissue pathology, but imaging prior to tissue sampling is helpful in guiding the differential. On CT imaging, ACC typically appears solid with irregular margins and nodularity. Infiltration of adjacent tissue and bony destruction may be evident. MR imaging is most useful for assessing possible perineural invasion and extension into the cavernous sinus and brain. Moderate enhancement of the lesion and T1/T2 isointense to muscle are also features of ACC on MRI (7).
Figure 4: Coronal, frontal, and sagittal views from CT maxillofacial with contrast at the time of follow-up, The CT demonstrates massive interval growth of the left orbital mass displaying both solid enhancing and cystic components. The epicenter of the mass appears to be in the left lacrimal gland There is marked left proptosis with compression and deformation of the left globe as well as medial displacement of the optic nerve and extraocular muscles. There is no definite sign of osteolysis of the orbital walls, however, there is bone remodeling with depression of the orbital floor. No evidence of intracranial extension of the left orbital mass.
what is this condition associated with?
Central skull base Fibrous dysplasia
Extensive fibrous dysplasia involvement of the cranial base in a patient with MAS. In patients with PFD or MAS, the anterior cranial base is involved in 95% of the cases as seen in this CT image.
Fibrous dysplasia (FD) is a non-malignant condition in which normal bone and marrow are replaced by fibrous tissue and haphazardly distributed woven bone [1, 2]. Patients may exhibit involvement of one bone (monostotic FD; MFD), multiple bones (polyostotic FD; PFD) or they may have McCune-Albright syndrome (MAS), which has been classically defined by the triad of PFD, café-au-lait skin macules and endocrinopathies, including among others, precocious puberty [3]. FD is caused by somatic activating mutations in the α subunit of the stimulatory G protein encoded by the gene GNAS [4, 5]. A related disorder, cherubism, is manifest by expansile, multiloculated, radiolucent fibro-osseous lesions with multiple giant cells located bilaterally and symmetrically in the jaws. Cherubism is genetically distinct from FD and will be discussed elsewhere in the Proceedings of this meeting.
Orbital Cavernous venous malformation
- Orbital Cavernous venous malformation
- AKA cavernous Hemangioma
- adults
- not a true neoplasm
- vascular malformation
- true capsule
- benign
- most common vascular orbital mass in adults
- usually in the lateral intra conal space
- well defined non-aggressive mass
- T2 bright
- progressive enhancement/fill in
Complications of orbital infection
- Cavernous sinus thrombosis
- superior orbital vein occlusion
- severe exposure keratopathy with secondary ulcerative keratitis
- neutrophic keratitis,
- secondary glaucoma,
- septic uveitis or retinitis,
- exudative retinal detachment,
- inflammatory or infectious neuritis,
- optic neuropathy,
- panophthalmitis,
- cranial nerve palsies,
- optic nerve edema,
- subperiosteal abscess,
- orbital abscess,
- central retinal artery occlusion,
- retinal vein occlusion,
- blindness,
- orbital apex syndrome,
- cavernous sinus thrombosis,
- meningitis,
- subdural or brain abscess, and
- death.
What are the different orbital spaces?
- Intraconal
- in the rectus muscle pyramid
- extraconal
- outside the rectus muscle pyramid
- preseptal
- postseptal
- Lacrimal fossa
Coloboma
Coloboma
- focal outpouching involving retina, choroid, iris.
- caused by deficient closure of fetal optic fissure
- located in region of optic disc
- a/w other congential globe, CNS and other systemic anomalies
Orbital infantile hemangioma
- AKA capillary hemangioma
Capillary haemangiomas of the orbit, also known as strawberry haemangiomas, on account of its colouring, or orbital infantile haemangiomas, are the most common orbital tumours of infancy, and unlike orbital cavernous haemangiomas, they are neoplasms rather than vascular malformations.
benign vascular tumour of infancy
- NO CAPSULE
- lobular or infiltrative hypervascular intensely enhancing mass
- T2 hyperintense
- flow voids may be visible
- most frequently superficial extraconal location
- may have post septal extension
- uncommonly presents as exclusively retrobulbar mass
- grows for less than a year and then typically involutes.
Sinonasal undifferentiated CA
- SNUC
- rare
- highly aggressive sinonasal malignancy
- Tumours tend to be rather advanced at presentation.
-
Radiographic features
- Tumours usually tend to be large at presentation, with poorly defined margins.
- Most arise within the ethmoid sinuses and superior nasal cavity.
- Aggressive features such as bone destruction may be seen.
-
Treatment and prognosis
- The prognosis for patients with SNUC is considered poor.
- Most centres may opt for varying degrees of craniofacial resection combined with adjuvant radiotherapy +/- chemotherapy.
Differential diagnosis
On imaging, it is almost impossible to differentiate from other tumours in this region with the possible exception of sinonasal mucosal melanoma 4.
Radiographic features of Coats disease
- Unilateral 90%
- retinal detachment with V-shaped contour
- dense vitreous/subretinal exudates
- Calc is uncommon
- Hyper on T1 and T2, proteinaceous and hemorrhagic exudate
- Nerve enhancement in advanced disease is a result of secondary glaucoma
- (picture:Case courtesy of Dr Michael Sargent, Radiopaedia.org, rID: 6089 small hyper echoic right globe)
Staphyloma
Staphyloma
- acquired defect of globe wall with thinning of the posterior sclera-uveal rim and protrusion of the choroid or sclera.
- On imaging elongated globe with focal deformity, usually posterior, but not as pronounced as coloboma
Nasal dermal Sinus anterior skull base lesion
Nasal dermal Sinus anterior skull base lesion
- midline developmental lesion anywhere from nasal tip to anterior skull base at foramen cecum.
- may be a/w nasal pit or repetitive bouts of meningitis clinically
- look for tract from nasal lesion to anterior cranial fossa
- may see widened foramen cecum +/- bifid crista galli
- may have associated dermoid/epidermoid along tract
Olfactory Neuroblastoma
cell origin
epidemiology
what are highly suggestive of the diagnosis?
-
aka
- esthesioneuroblastoma
-
intro:
- a malignant tumor arising from olfactory mucosa in the superior nasal cavity
-
radfeatures:
- heterogeneously enhancing mass in the upper nasal cavity
- larger tumors extend to the floor of the anterior cranial fossa with erosive bone changes
- may have a waist at the level of the cribriform plate
- Peripheral tumor cysts at the intracranial tumor-brain margin are highly suggestive of the diagnosis.
-
Epidemiology
- There is bimodal age distribution with one peak in young adult patients (~2nd decade) and another peak in the 5th to 6th decades.
- There is no recognised gender predilection.
-
Pathology
- Olfactory neuroblastomas are of neural crest cell origin 1.
- Macroscopically, they are multilobulated pink-grey tumours.
-
Histology:
- variable differentiation, from well-formed neural tissue to undifferentiated neuroblasts with pseudorosette formation 2.
- It has been suggested that olfactory neuroblastoma is actually part of the Ewing sarcoma group of tumours, rather than being related to neuroblastoma 5.
List the structures of the Globe and the Orbit
- Globe
- anterior chamber
- posterior chamber
- vitreous
- lense
- sclera
- choroid
- retina
- Orbit
- Intraconal fat
- Extraconal fat
- optic nerve
- optic nerve sheath
- ophthalmic artery
- ophthalmic vein
- rectus muscles
Central skull base lymphoma
Central skull base lymphoma
- lymphoma
- may orginate in bone or from dura. wide range of appearances
- typically enhance uniformly
- can be dural based
- can involve bone with lytic changes
- extensive soft tissue mass
- relatively restricted diffusion with low ADC
- Wang, Liang et al. “Primary non-Hodgkin’s lymphoma of the skull base: A case report and literature review.” Clinical Neurology and Neurosurgery 115 (2013): 237-240.
- may orginate in bone or from dura. wide range of appearances
- Orbital Dermoid Cyst
- Common orbital tumour in childhood
- typically presents in the 1st 2 decades
- Congenital
- closed sacs lined by an ectodermal epithelium
- most common orbital mass in children.
- They are typically divided into:
- deep (within the orbit) and
- superficial (adjacent to the orbital rim).
- Rad features
- Hypodense on CT and High T1 sig are diagnostic (ie Fat signal/density)
- Contiguous bone scalloping or sclerosis is common
- May contain debris (inhomogeneous MRI signal)
- Calcification present occasionally
Central skull base Pagets
- Central skull base Pagets
- Primary metabolic bony disease. Often asymptomatic. Typically seen in older adults, M>F.
- may be multifocal diseae with mixed lytic sclerotic pattern
- well definded lytic regions with bone expansion in early phase. Cotton wool appearance later in lytic sclerotic phase
- MRI hypointense T1 and heterogenous enhancement.
sinonasal SCC
- most common primary sinonasal malignancy
- the ethmoid sinus and nasal cavity primaries may extend to the anterior skull base
- an aggressive lesion with bone destruction
- Case courtesy of Dr Smita Deb, Radiopaedia.org, rID: 31162
Radiographic Features of PNS
asymmetry and soft tissue infiltration in PPF, neural foramina, widening of these structures when more advanced.
Contrast enhanced high res MRI is the optimal technique for evalulation of perineural spread of tumour.
May also see secondary findings: denervation changes
Axial CT (a and b) and axial T1-weighted (c and d) images show obliteration of the preantral fat pad on the left (long white arrow in a and c) when compared to its normal appearance on the right (short white arrow in a and c). In addition, note the enhancing soft tissue within the maxillary sinus (black arrow in a) as well as the obliteration of the fat pad in the left pterygopalatine fossa (long white arrow in b and d) compared to its normal appearance on the right (short white arrow in b and d). The obliteration of the fat pad in the left pterygopalatine fossa (long white arrow) can also be well appreciated on coronal images (e). These signs are indicative of PTNS along V2 in this patient with history of left cheek skin cancer presenting with V2 numbness
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6269343/
what is this?
- Venolymphatic malformation of the orbit
- Multiloculated, transspatial lesions
- Those with significant laympohait component tento be more cystic and have propensity to hx with fluid fluid levels
- those with predominantly venous component tend to have more homogenous enhancement.
axial Myopia
axial Myopia
- Axial myopia
- AP elongation but no protrusion
Rad Features of Optic Nerve Glioma
- Tumour growth
- tubular
- excrescent
- fusiform widening of the optic nerve
- Enlargement of the optical canal > 1mm difference between left and right is abnormal
- Lower CT density than meningioma
- Contrast enhancement variable
- Calcs are rare (cf meningioma)
- Tumour extension best seen on MRI
- chiasm
- optic tracts
- Lateral geniculate body
- Optic radiation
Sinonasal Osteoma
- Well defined non-aggressive bony mass
- most common in frontal and eithmoid sinuses
Lacrimal Gland Tumours
- Lymphoid
- benign reactive lymphoid hyperplasia
- lymphoma
- Epithelial tumours
- benign mixed (pleomorphic) tumour (most common)
- ACC
- Mucoepidermoid CA
- Malignant mixed tumour (carcinoma ex pleomorphic adenoma) (picture)
- A 68-year-old woman with a history of 2 prior right orbital excisions elsewhere over 10 years previously for a pleomorphic adenoma presented with a painless progressive lacrimal fossa mass. Examination revealed right inferomedial globe dystopia from a lacrimal mass (Fig 1A). Orbital magnetic resonance imaging disclosed an enhancing nodular lacrimal gland mass with medial extension (Fig 1B). Incisional biopsy showed hyalinized nodules comprised of ducts, myoepithelial cells, and myxoid stroma. Ductal cells exhibit marked atypia, prominent nucleoli, and frequent mitosis consistent with carcinoma ex pleomorphic adenoma (Fig 1C). Systemic work up showed no extraorbital disease.
- https://www.aaojournal.org/article/S0161-6420(16)30266-4/fulltext
Sinonasal lymphoma
-
Rad features:
- Cephalad extension from nasal cavity through skull base
- typically homogenous lesions with relatively high density on NCCT
- septal destruction, occasional bone remodeling
- on MRI relatively low signal on T2 images. homogeneously enhancing
-
Intro
- Sinonasal lymphoma refers to the involvement of the nasal cavity and/or paranasal sinuses with lymphoma. It can be primary or secondary.
-
Clinical presentation
- The most common locations of sinonasal lymphoma are the nasal cavity and the maxillary sinus.
- Generally, T-cell lymphoma (especially nasal T/NK-cell lymphoma), commonly seen in the Asian and South American populations, most frequently involves the nasal cavity.
- B-cell lymphoma commonly seen in the Western populations, usually involves the paranasal sinuses 5.
-
Pathology
- It can be represented by various cytological types but the most common forms to arise in the sinonasal area is thought to be DLBCL (diffuse large cell B cell lymphoma),
- followed by nasal NK/T-cell lymphoma 3.
- There is a predilection for the nasal cavities involvement over the paranasal sinuses.
-
Radiographic features
- Sinonasal lymphomas may be either seen as diffusely infiltrating lesions extending along walls of paranasal sinuses and nasal cavity or as discrete sinonasal soft tissue mass-like lesions.
-
Differential diagnosis
- sinonasal granulomatosis with polyangiitis
-
sinonasal carcinoma
- adenocarcinoma
- squamous cell carcinoma (SCC)
-
esthesioneuroblastoma
- superior portions of the nasal cavity, near the cribriform plate
- sinonasal melanoma
Central skull base pituitary macroadenoma
Central skull base pituitary macroadenoma
ResearchGate
Pituitary adenoma in a 38-year-old man
- Pituitary macroadenoma
- may extend inferiorly to clivus or sphenoid sinus
Case courtesy of Dr Bruno Di Muzio, Radiopaedia.org, rID: 47575
What is Retinal detachment?
Separation of the sensory retinal from the outer pigmented epithelium.
Appears in a characteristic V shape, with the apex of the detachement at the optic disc.
The presence of retinal or choroidal detachment may be caused by an ocular mass.
Base of skull arachnoid granulations
- lesions found along dural sinuses and dural surface. Typically incidental. But in patients with CSF leaks may represent the site of osteodural defect.
Aberrant arachnoid granulations, also known as arachnoid pits, are arachnoid granulations that penetrated the dura but failed to migrate normally in the venous sinus. They are most often located in the greater wing of the sphenoid bone and may be seen in idiopathic intracranial hypertension. Occasionally, they are seen in the posterior temporal bone wall.
Terminology
Aberrant arachnoid granulations are known by a variety of other names such as sphenoid wing meningoceles (often used in the context of idiopathic intracranial hypertension with or without rhinorrhoea), intradiploic arachnoid cysts and arachnoid pits 5,6.
Clinical presentation
Although most are incidental finding when associated with elevated intracranial CSF pressures (e.g. idiopathic intracranial hypertension) they may enlarge and present with cerebrospinal fluid rhinorrhoea or cephaloceles 5.
Pathology
Aberrant arachnoid granulations can be seen at the floor of the anterior and middle cranial fossa and, less frequently, at the posterior temporal bone wall. They contain cerebrospinal fluid but do not communicate with the dural venous sinuses. Instead, the pressure of the cerebrospinal fluid will cause bone erosion.
As they grow, these arachnoid granulations can cause defects in the posterior temporal bone wall or the tegmen tympani. Thus, cerebrospinal fluid otorrhoea can occur. Arachnoid granulations in this specific location may also potentially spread bacterial infection to the meninges. In this context, it is important to report their presence, especially since they are known to enlarge with age.
Case courtesy of Dr Balint Botz, Radiopaedia.org, rID: 81576
what does ocular melanoma arise from?
- arises from pigmented choroidal layer
- retinal detachment is common
- Well defined sharply marginated fungating soft tissue lesion arising from the uveal coating of the superior quadrant of the left eye globe. It displays bright signal on T1, low signal on T2 with avid enhancement on post contrast study. No extra ocular extension and with clear retro orbital fat.
- https://radiopaedia.org/cases/primary-uveal-melanoma
what is this?
Venous Varix
- distensible venous channel with systemic connection
- dynamic enlargement of lesion with valsalva
- may not be visible when patient relaxed
- may present with thrombosis or hx
What are the clinical and radiographic features of PHPV?
- Clinical
- blindness
- leukokoria
- microphthalmia
- unilateral more common
- Radfeatures
- microphthalmia
- vitreous body hyperdensity along the remnant of the hyaloid artery
- No calcification
- V - shaped retinal detachement
- Layering of blood
- Triangular retrolental soft tissue mass.
- Stalk like hyaloid remnant
r
There is a soft tissue mass arising from the marrow of the clivus with cortical expansion and destruction. No local infiltration observed at this stage. A further osteolytic soft tissue mass is present at the right transverse process of C2.
Case Discussion
Typical location for myelomatous lesion in the skull base include Clivus, petrous apex, occipital condyle, greater wing of sphenoid with additional lytic foci of calvaria & facial bones.
- Central skull base Multiple myeloma
- commonly lytic, multiple, may be indistinguishable from extensive mets with lytic pattern
Case courtesy of Dr Charlie Chia-Tsong Hsu, Radiopaedia.org, rID: 19892
Rad features of Optic Neuritis in the acute phase
- Coronal T2 or post Gd T1 Fatsat best for dx
- T2: the obliteration of the periotpic space
- increased T2 sig of the affected optic nerve
- enhancement of the optic nerve
what is this??
- Optic Head Drusen
- focal calcification in hyaline bodies in the optic nerve head
- Drusen is usually bilateral and asymptomatic
- may be a/w macular degeneration
- blurred disc margins may be mistaken for papilledema
- On ct seen as punctate hyperdensity most commoly at optic nerve head or macula
When does choroidal deattachment occur?
- choroidal detachement
- usually results after ocular surgery, trauma or uveitis causing fluid to accumulate in the choroidal space.
- Characteristic appearance spares the posterior ⅓ of the globe (region of the optic disc), in contradistiction with retinal detachment
Epidemiology of Optic nerve sheath meningiomas
Association with x
- forth and fifth decades
- F>M
- younger patients typically have NF2
- Clinically:
- progressive vision loss
Ecchordosis Physaliphora
Ecchordosis Physaliphora
Cystic lesion in the prepontine cistern without enhancement or restricted diffusion extending into bone.
Absence of enhancement or restricted diffusion together with non-aggressive bony margins in this location is typical of a retroclival ecchordosis physaliphora, a notochord remnant.
Ecchordosis physaliphora is a congenital benign hamartomatous lesion derived from notochord remnants, usually located in the retroclival prepontine region, but can be found anywhere from the skull base to the sacrum.
Terminology
There has been some controversy as to whether intradural chordoma and large ecchordosis physaliphora are different entities. Some authors (such as Wolfe et al.) proposed the name ‘intradural chordoma’ for all intradural notochordal remnant lesions 8. Others (such as Rodriguez et al.) proposed that all intradural notochordal remnant lesions should be called ecchordosis physaliphora, until chordoma are pathologically proven to arise from the intradural compartment 9. However, they are currently considered distinct pathologies with a common origin.
Clinical presentation
Unlike chordomas which are often symptomatic due to brainstem or cranial nerve compression, patients with ecchordosis physaliphora are usually asymptomatic. They are found in ~2% of autopsies 1.
Pathology
Ecchordosis physaliphora arise from remaining notochord cells along the axis of the spine after embryogenesis. Unfortunately, ecchordosis physaliphora and chordoma are histologically indistinguishable, other than by examining the margins, the latter demonstrating infiltrative growth.
DDx of Perineural Tumour Spread
-
Nerve sheath tumours
- tubular, fusiform, lobular mass along nerve or nerves
- Typically larger than perineural tumour spread
- no other primary h+n tumour/ malignancy
-
Skull base meningioma
- homogenously enhancing dural based mass
- may extend into neural foramina, jugular foramen or PPF
-
Invasive fungal sinusitis
- Immunocompromised patients including diabetics
- infiltrating disease but does not follow nerves exclusively
Absent mucosal enhancement in the left ethmoid and sphenoid sinus is highly concerning for invasive fungal sinusitis.
Absent enhancement indicates mucosal necrosis from acute invasive fungal sinusitis (AIFS) and was confirmed at surgery. Picture
-
Sarcoidosis
- nerve involvement may mimic perineural tumour spread
- absence of primary h+n malignancy
- may have other associated findings such as dural based inflammation, leptomeningeal component
Sinonasal nerve sheath tumor
- http://www.ajnr.org/content/27/4/929
- benign neoplasm arising from peripheral nerve Schwann cells
- well defined lesion with smooth remodeling
- enhancing sharply marginated mass may have internal cystic changes.
Pathology of Dermoid Cyst vs Epidermoid Cyst
Pathology
Dermoid cysts are thought to occur as a developmental anomaly in which embryonic ectoderm and mesoderm are trapped in the closing neural tube between the 5th-6th weeks of gestation 1,3.
Stratified squamous epithelium lines dermoid cysts, as in epidermoid cysts, which are both considered ectodermal inclusion cysts.
Unlike epidermoid cysts, however, Dermoid Cysts also have adenxal tissues derived from mesoderm, such as hair follicles, sweat glands, and sebaceous glands.
The latter is responsible for the secretion of sebum which imparts the characteristic appearance of these lesions on CT and MRI.
Central skull base chordoma
- Central skull base chordoma (Clivus)
- rare
- locally aggressive tumour arising from primitive notochord remnants
- can present with h/a and diplopia secondary to CN VI involvement in Dorello canal. Other nerves may be involved depending on extent
- expansile destructive midlein clival masss. bay be near sphenooccipital synchondrosis
- classically high signal on T2 secondary to high water content
- can also have mix of calcification , hemorrhage and mucoid material with high T1 and low T2
- enhancing lesion with honey comb pattern.
MR imaging of 2 patients with SBC. Patient 1 (A–C), 21-years of age. Pathologic findings were conventional chordoma. The patient underwent subtotal tumor resection with no progression at 48 months. A, Axial T2-weighted MR imaging. Tumor demonstrates homogeneous high signal intensity. B, Axial T1 FLAIR-weighted MR imaging. Tumor has relatively homogeneous hypointense signal compared with the pons. C, Enhanced T1 FLAIR MR imaging shows no enhancement of the lesion. Patient 2 (D–F), 25 years of age. Pathologic findings revealed conventional chordoma with necrosis and nuclear division. This patient underwent subtotal tumor resection with tumor progression at 8 months. D, Axial T2-weighted MR imaging demonstrates tumor heterogeneity. The signal intensity is relatively lower than that in patient 1. E, Axial T1 FLAIR MR imaging. The tumor is heterogeneous and hyperintense compared with the pons. F, Enhanced T1 FLAIR MR imaging. Tumor exhibits moderate enhancement.
MR Imaging Grading System for Skull Base ChordomaK. Tian, L. Wang, J. Ma, K. Wang, D. Li, J. Du, G. Jia, Z. Wu and J. ZhangAmerican Journal of Neuroradiology June 2017, 38 (6) 1206-1211; DOI: https://doi.org/10.3174/ajnr.A5152
