Hot Seat Flashcards
Erdheim Chester Disease
Radiographic features
Musculoskeletal involvement is most common, with multifocal extraskeletal involvement seen in 30-50% of patients 1,2.
Skeletal involvement
bilateral, symmetric metaphyseal and diaphyseal sclerosis 1,2
increased uptake on Tc-MDP bone scan 7
cortical thickening
Visceral
lung (see: pulmonary manifestations of Erdheim-Chester disease)
can appear similar to Langerhans cell histiocytosis with predominantly cystic disease, septal thickening and preserved lung volume
chest radiographs will often show interstitial oedema pattern (interlobular septal thickening) with cardiomegaly and pleural effusions that do not respond to diuretics
kidneys and retroperitoneum
often involved
usually asymptomatic 1
hairy kidney sign: irregular symmetric infiltration of the bilateral perirenal and posterior pararenal spaces 11
coated aorta sign: periaortic soft tissue 11
inferior vena cava and pelvic ureters are typically spared, which are useful cross-sectional imaging findings for differentiation of retroperitoneal Erdheim-Chester disease from retroperitoneal fibrosis 8
skin
retro-orbital tissue
optic nerve oedema
retrobulbar masses that can cause proptosis and motility impairment 13
retrograde extension along the optic nerve to the hypothalamus may explain the distribution of brain involvement 4
heart, pericardium and aorta 2
Intracranial
Intracranial involvement of the dura, brain and pituitary are rare 3:
meninges
dural accumulations may mimic meningiomas, with enhancing soft tissue masses
T2 signal characteristics are somewhat different, as the accumulations in Erdheim-Chester disease are hypointense 3
brain
most commonly affecting the pons and cerebellum 14
can also affect the hypothalamus 3,14
intraparenchymal masses appear non-specific 10
pituitary infundibulum 14: presenting with diabetes insipidus
Browns Tumour
A brown tumour, also known as osteitis fibrosa cystica and rarely as osteoclastoma,
Hyperparathyroidism
Look for parathyroid adenoma
Lytic bone lesion differential
F: fibrous dysplasia (FD) or fibrous cortical defect (FCD)
E: enchondroma or eosinophilic granuloma (EG)
G: giant cell tumour (GCT) or geode
N: non-ossifying fibroma (NOF)
O: osteoblastoma
M: metastasis(es)/myeloma
A: aneurysmal bone cyst (ABC)
S: simple (unicameral) bone cyst
H: hyperparathyroidism (brown tumour)
I: infection (osteomyelitis) or infarction (bone infarction) or intraosseous lipoma
C: chondroblastoma or chondromyxoid fibroma
Sarcoidosis
pulmonary and mediastinal manifestations
cardiac manifestations
musculoskeletal manifestations
head and neck manifestations
central nervous system manifestations
abdominal manifestations
cutaneous manifestations
Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH)
an extremely rare but underdiagnosed pulmonary disorder at the benign end of the neuroendocrine cell proliferation spectrum of preinvasive lesions of the lungs.
CT
Characteristic findings suggest the diagnosis, which is usually clinically occult 13:
multiple small solid nodules in a peribronchovascular distribution, more numerous peripherally and with a lower zone predominance
mosaic attenuation due to a combination of air trapping and regional oligaemia as a result of constrictive bronchiolitis
nodular bronchial wall thickening (cell clusters), mucus plugging, and bronchiectasis are common
MIP slabs aid in small nodule detection. MinIPs and expiratory CT highlight air-trapping.
Neurofibromatosis 1
As is the case with many phakomatoses, NF1 results in a variety of abnormalities of variable severity. To make the clinical diagnosis two or more of the following are required 2:
≥2 neurofibromas or ≥1 plexiform neurofibroma
optic nerve glioma
distinctive osseous lesion (such as sphenoid wing dysplasia or thinning of long bone cortex with or without pseudoarthrosis)
>6 café au lait spots evident during one year (prepubertal >0.5 cm, postpubertal >1.5 cm in size)
axillary or inguinal freckling
≥2 iris hamartomas (Lisch nodules)
a primary relative with NF1
phaeochromocytoma
malignant peripheral nerve sheath tumour (MPNST) (~10% of patients) 7
Wilms tumour
rhabdomyosarcoma
renal angiomyolipoma
glioma
juvenile pilocytic astrocytoma (~20% of patients) 13
optic nerve glioma
diffuse brainstem glioma
spinal astrocytoma and spinal pilocytic astrocytoma 9
carcinoid tumour(s)
leiomyoma(s)
leiomyosarcoma
ganglioglioma
leukaemia
high grade astrocytoma with piloid features
NF1 cancers
phaeochromocytoma
malignant peripheral nerve sheath tumour (MPNST) (~10% of patients) 7
Wilms tumour
rhabdomyosarcoma
renal angiomyolipoma
glioma
juvenile pilocytic astrocytoma (~20% of patients) 13
optic nerve glioma
diffuse brainstem glioma
spinal astrocytoma and spinal pilocytic astrocytoma 9
carcinoid tumour(s)
leiomyoma(s)
leiomyosarcoma
ganglioglioma
leukaemia
high grade astrocytoma with piloid features
NF1 CNS findings
FASI (focal areas of signal intensity): occur in deep white matter and basal ganglia or corpus callosum 5, areas of T2/FLAIR hyperintensity with no contrast enhancement
optic nerve glioma or optic pathway glioma (may manifest as enlarged optic foramen)
progressive sphenoid wing dysplasia
J-shaped sella
lambdoid suture defects
dural calcification at the vertex
moyamoya phenomenon (rare)
buphthalmos
Skeletal NF1
Skeletal
Manifestations include:
kyphoscoliosis
posterior vertebral scalloping
hypoplastic posterior elements
enlarged neural foramina
ribbon rib deformity, rib notching, and dysplasia
dural ectasia
tibial pseudoarthrosis or, less commonly, ulnar pseudoarthrosis
bony dysplasias: especially affecting the tibia
severe bowing, gracile bones 11
multiple non-ossifying fibromas
limb hemihypertrophy
Thoracic NF1
mediastinal masses
neurofibroma
lateral thoracic meningocele: typically on the convex side of scoliosis (through widened neural foramina)
extra-adrenal phaeochromocytoma (paraganglioma)
lung parenchymal disease: ~20%
diffuse interstitial fibrosis: lower zone
bullae formation: upper zone
secondary pulmonary arterial hypertension and cor pulmonale
Thoracic NF1
mediastinal masses
neurofibroma
lateral thoracic meningocele: typically on the convex side of scoliosis (through widened neural foramina)
extra-adrenal phaeochromocytoma (paraganglioma)
lung parenchymal disease: ~20%
diffuse interstitial fibrosis: lower zone
bullae formation: upper zone
secondary pulmonary arterial hypertension and cor pulmonale
Vascular and cutaneous NF1
aneurysms and arteriovenous malformations
renal artery stenosis
coarctation of aorta
cutaneous and subcutaneous neurofibromas: benign peripheral nerve sheath tumours
presented as small soft tissue skin nodules on radiological images
Cystic advential disease
Cystic adventitial disease is an uncommon vascular pathology predominantly affecting peripheral vessels. The vast majority of cases occur in arteries, with venous involvement being an extremely rare occurrence 8.
Surgical bypass situation
Epidemiology
It typically affects young to middle-aged individuals without evidence of atherosclerosis or other systemic vascular diseases. There is a recognised male predilection with a M:F ratio of ~15:1 9.
Clinical presentation
Although cystic adventitial disease can affect any peripheral vessel, there is a striking predilection in the popliteal region, affected in ~85% of cases 1,3,4.
Typical symptoms include:
rapidly progressive calf claudication 1,3
lower extremity pain
Pathology
The condition is characterised by a collection of mucinous material (mucous cysts) within the adventitial portion of the wall of the affected vessel.
MRI
Appearances on MRI are variable, depending on the distribution and size of the cysts.
It may be seen as aggregates of multiple small round/ovoid masses originating in the affected arterial wall, which if concentric lead to hourglass stenosis. When the lesions are large, they can have a multiloculated appearance and can displace the artery to one side, the so-called “scimitar sign” 4.
Lesional signal characteristics include:
T1: individual lesions are of variable signal dependent on mucoid content 4
T2/STIR: individual lesions are high signal 1,4
