Key Differentials.

Question 1

Acro- osteolysis

Answer 1

PINCH-FO

Psoriasis/pyknodysostosis
Injury-thermal burn or frostbite
Neuropathy-diabetes or leprosy
Collagen vascular disease- scleroderma/raynaud 
Hyperparathyroidism
Familial- Hajdu Cheney 
Other - PVC

Question 2

Metaphyseal lines

Answer 2

Lucent: LINING
Leukaemia/lymphoma
Infection (STORCH)
Normal variant
Illness: systemic e.g. rickets, scurvy
Neuroblastoma mets
Growth arrest lines (Harris growth resumption lines)

Dense: PRINCES
Poisoning: heavy metals
Rickets
Infection (torch) 
Neoplastic: lymphoma/leukaemia, normal variant
Congenital syphilis
Endocrine: hypothyroid, hypercalcaemia
Scurvy, sickle cell

Alternating:
Growth arrest, bisphosphonates, rickets, osteopetrosis, chemo, chronic anaemia, treated leukaemia

Question 3

Erlenmeyer flask

Answer 3

Lead GNOME

Lead poisoning
Gaucher 
Neiman-Pick
Osteopetrosis, osteochondromatosis
Metaphyseal dysplasia and craniometaphyseal dysplasia
‘Ematological: thalassaemia

Question 4

Cerebral rim enhancing lesion

Answer 4

Magic dr

Met abscess gbm infarct contusion demyelination radiation necrosis

Question 5

Idiopathic intracranial hypertension vs intracranial hypotension vs nph

Answer 5

Pseudotumour cerebri: overweight woman in 40s with headache. Slit like ventricles, empty sella, distended Meckels cave, increased csf around tortuous optic nerves, papilloedema, effaced sinuses, tonsillar ectopia, can get CN6 palsy
Intracranial hypotension: also middle aged women;subdural, enhancing pachymeninges, enlarged sinuses, pituitary engorgement, sagging cerebellar tonsils (seeps).
Nph: wet, wacky, wobbly; ventriculomegally out of proportion with atrophy, Evans index>0.3, temporal horns >6mm, acute callosal angle

Question 6

Carney triad complex and syndrome

Answer 6

Complex: myxoma, blue naevus
Syndrome: gastrointestinal stromal sarcoma, extra adrenalmphaeochromocytoma
Triad: gist, extra adrenal phaeochromocytoma, pulmonary chondroma

Question 7

Papillary necrosis

Answer 7

RO NSAIDs

Renal vein thrombosis, obstruction
Nsaids 
Sickle cell
Acetamenophen 
Infection - pyelo, Tb
Diabetes

Question 8

Medullary calcinosis

Answer 8

Hyperparathyroid
Acidosis (renal tubular)
Medullary sponge
Hypercalcaemia
Oxalosis
Papillary necrosis

Question 9

Cortical calcinosis

Answer 9

Glomerulonephritis
Oxalosis
Acute cortical necrosis
Transplant rejection

Question 10

Fat containing suprarenal lesion

Answer 10

Myelolipoma
Liposarcoma
Exophytic AML
(Adenoma is intracytoplasmic fat)

Question 11

Adrenal mass

Answer 11

Adenoma: <10HU (lipid rich) or out of phase drop out or >40% relative/>60% absolute washout
80% conn adenoma/20% hyperplasia, 80% Cushing hyperplasia/20% adenoma
Hyperplasia: >10mm width without mass
Myelolipoma
Adrenocortical carcinoma >6cm, 30% calcify
Phaeochromocytoma >3cm, T2 hyperintense, may be bilateral if MEN2
Met smaller, known ca
Lymphoma, diffuse

Question 12

Paediatric hepatic mass

Answer 12

IHH-solid, hypervascular, newborn.
heterogeneous hyper vascular solid mass, early progressive peripheral enhancement, 50% ca, heart failure. Normal afp
Mesenchymal hamartoma- cystic in neonate/infant.
<2yo. Generally large multicystic but spectrum cystic - solid. Ca/Hg uncommon. Enhances. Normal AFP
Hepatoblastoma- solid, hypovascular in infant/toddler.
solid, heterogenous, 50% ca. 90% AFP. <5yo.