Endocrine Flashcards
Adrenal anatomy
Paired retroperitoneal above each kidney. If congenital absent kideny, adrenal takes on ‘pancake’ shape
Sup arterial from inf phrenic
Mid arterial from aorta
Inf arterial from renal artery.
Venous to IVC or L renal vein
Zona glomerulosa - aldosterone
Zona fasciculata - cortisol
Zona reticularis - androgens
Medulla - catecholamines
Triple stripe oreo appearance on USS in babies: hypoechoic cortex, hyperechoic medulla, hypoechoic cortex
Neuroblastoma
Form in adrenal medulla and typically look like elarged gland with hyperechoic component. Can also have cystic components and haemorrhage
Adrenal haemorrhage
Usually in trauma or stress. Enlarged gland with anechoic component
STRESS
Seen after breech birth but aso with fetal distress and congenital syphilis. Imaging diff depending on age of haemorhage but end result calcification. favours right side
TRAUMA
Adult in setting of trauma. More common in setting of trauma
Wterhouse Friderichsen Syndrome - haemorrhage in setting of meningitis
Hyperplasia
Big adrenal, looks like a brain with wrinkled surface. Longer than 20mm and limb thicker than 4mm
21 HYDROXYLASE DEFICIENCY
If stem mentions genital ambiguity then this is answer. results in congenita adrenal hypertrophy. Genital ambiguity in girls and salt losing in boys
TOO MUCH CORTISOL
Overproduction of ACTH resulting in bilateral adrenal gland hyperplasia.
Cushing disease is overproduction by pituitary adenoma, most common cause 75%
Cushing syndrome is variety of causes with common symptoms such as ACTH secreting tumour usually lung SCC. or overproduction b adrenaladenoma or high dose steroids
Adrenal adenoma
Most common adrenal tumour, 8% people.
NON CON
<10HU
CONTRAST
Delayed/non-con x 100. If >60% is adenoma
Enhanced-delayed/enhanced x 100. If >40% is adenoma
Hypervascular mets can mimic adenoma. If HU >120 should think met. Phaeochromocytomas can also mimic if HU >120 arterial or PV
MRI want to see drop out on in and out of phase
Adrenal lesion tricks for exam
Adenomas usually homogenous. If haemorrage, calcs, necrosis think about other things
Adenomas usually <3cm. Bigger mass more likely to be malignant with exception of bluk fat myelolipomas or phaeos
Bilateral small probably adenomas
Bilateral large
Bilateral large phaeo or met
PV >120HU probably met RCC/HCC or phaeo
Collision tumour
Two different tumours smash together, usually one an adenoma. PET and MRI can usually differentiate.
Conns syndrome
Syndrome of excessive aldosterone production. Most commonly from benign adenoma. Cortical carcinoma a possibility but much more rare.
Phaeochromocytoma
Large at presentation >3cm. Look is variable (heterogenous, homogenous, cystic areas, calcs, sometimes fat).
CLassic is heterogenous mass with avid enhancement.
MRI T2 bright. MIBG uptake. Can be extra adrenal suchs as organ of Zuckerkandl along aorta around IMA
Remember to check on any phase, if >120 not an adenoma.
RULE OF 10s 10% extra-adrenal 10% bilateral 10% in children 10% hereditary 10% NOT active
SYNDROMES
VHL, MEN2a and 2b
Can be in NF1, Sturge Weber and TS
CARNEY TRIAD
Extra adrenal phaeo, GIST, Pulmonary hamartoma
Adrenal myelolipoma
Benign tumour that contains bulk fat. 1/4 have calcs
If big they can bleed and present with retroperitoneal haemorrhage.
Asociated with: Cushings, Conns, CAH
Can result in discontiuous diaphragm artefact on USS
Miscellaneous
ADRENAL CYST
Often unilateral and can be any size. Thin wall, no enhancement.
METS
Breast, lung and melanoma. No specific findings, look like lipid poor adenoma.
CALCs
Often prior trauma or infection. Melanoma mets calcify Certain tumours (cortical carcinoma, neuroblastoma, myelolipoma)
CORTICAL CARCINOMA
Large 4-10cm. Can be functionsl (Cushings). Calcify 20%. Bad and met everywhere. Unlikely to be <5cm. Often has central necrosis.
WOLMAN DISEASE
Aunt Minnie. Bilateral enlarged calcified adrenals. Fatal in first year of life.
Multiple Endocrine Neoplasia (MEN)
MEN1 (3 Ps)
Pituitary denoma
Parathyroid hyperplasia
Pancreatic Tumours
MEN 2a (1M 2P)
Medullary thyroid Ca
Phaeochromocytoma
Parathyroid hyperplasia
MEN 2b (2Ms 1P)
Medullary thyroid Ca
Marfanoid Habitus and Mucosal Neuroma
Phaeochromocytoma
Carcinoid syndrome
Flushing, diarrhoea, pain, right heart failure from seretonin manufactured by carcinoid tumour. Does not occur until mets to liver.
Typical location for primary is GIT 70%, usually distal ilium. Syndrome only occurs in 10% cases
GI carcinoids are associated with other GI tumours like adeno
Urine test for carcinoid is 5HIAA. Octreotide scan is scan of choice.
MIBG is always positive. Systemic seretonin degrades heart valves and causes tricuspid regurg
Von Hippel Lindau
Hemangioblastoma (retina, cerbeellum, spinal cord)
Endolymphatic Sac Tumour (ELST) 10%
Bilaterl Clear Cell RCC (VHL clear cell) 70%
Papillary cystadenoma epididymis 55%
Phaeochromocytoma 10%
Pancreatic cysts and serous cystadenomas 75%
PGL Syndrome (paraganglioma and Phaeochromocytoma)
Multiple head and neck paraganglioma 70%
Phaeochromocytoma risk variable depending on subtype
Tuberous Sclerosis (Bourneville disease)
Triad - facial angiofibroma, seizures, retard brain
Subependymal Giant Cell Astrocytomas SEGAs
Cortical tubers, subependymal nodules
Ranal AMLs 80%
Cardiac rhabdomyomas
Pulmonary Cysts and LAM
Thyroid anatomy
butterfly gland, two lobes connected by isthmus. Descends from foramen cecum at anterior midline base of tongue along with thyroglossal duct. Posterior nodular extension of thyroid (Zuckerkandl tubercle) helps locating RLN which is medial
Thyroid nodules
Suspicious features:
more solid, calcs.
Microcalcification supposedly buzzword for papillary thyroid ca.
Comet tail seen in colloid
Cold nodules on I-123 are benign but have cancer 15% time so get worked up
Colloid nodules
Common. Suspicious features include microcalcs, increased vascularity, solid, size >15mm and cold on nuc uptake scan. COmet tail artefact is buzzword
Thyroid adenoma
Look like solid colloid nodules. Hyperfunctioning (hot on nuc uptake). If hyperfunctioning (toxic adenoma), background thyroid will be colder than normal.
Goiter
Enlrged thyroid. In America, multinodular goiter or Graves. In Africa, low idodine. Usually asymptomatic but can get compressive symptoms on trachea of esophagus.
Acue suppurative thyroiditis
Bacterial infection of thyroid, can get abscess. In kids, infection can start in 4th branchial cleft anomaly (usually on left), travel via a pyriform fistula then infect the thyroid.
Subacute thyroiditis/De Quervains thyroiditis
Female with painful gland after an upper respiratory tract infection. Get hyperthyroidism then later hypothyroidism.. Gland recovers to normal function after cold.
Reidels thyroiditis
IgG4 disease (orbital pseudotumour, retroperitoneal fibrosis, schlerosing cholangitis). Women 40-70. Thyroid replaced by fibrous tissue and diffusely enlarges and compresses adjacent structures. Decreased vascularity. MRI dark on all sequences
Thyroglossal Duct cyst
Most common congenital neck cyst in paeds. Can occur anywhere between foramen cecum and thyroid gland. Looks like thin walled cyst.
Can get infected, can have ectopic thyroid tissue, rarely ectopic thyroid can get papillary thyroid ca.
25% suprahyoid
30% at hyoid
45% infrahyoid
THEREFORE at/or above hyoid is most common location when combined.
Ectopic and lingual thyroid
Anywhere from base of tongue through central neck. Most common 90% is at tongue base (lingual thyroid).
Hypderdense due to iodine content, same as normal thyroid. Check for normal thyroid when this is seen.
Graves
Autoimmune disease that cases hyerthyroidism. Primarily from antibody directed at TSH receptor. TSH levels will be low. Gland enlarged and hot on doppler.
Graves orbitopathy: spares tendon insertions (coke bottle), painless, increased intraorbital fat. IMSLO order
Hashimotos
Most common cause of goitrous hypothyroidism. Autoimmune disease that causes hyper then hypothyroidism as gland burns out. Increased risk primary thyroid lymphoma. Antibodies to thyroid proxidase TPO and antithyroglobulin.
Heterogenous ‘giraffe skin’ appearance.
‘White Knights’ uniform hyperechic nodules are regenerative nodules
Thyroid cancer
4 main subtypes. Additionally can get mets or lymphoma.
PAPILLARY
Most common
Microcalfications is buzzword.
Mets via lymphatics, excellent prognosis, responds to I-131
FOLLICULAR
Second most common.
Mets haematogenously to bones/lungs/liver. Survival still ok. Responds to I-131
Hurthle cell is uncommon variant in elderly
MEDULLARY Uncommon Assocaition with MEN2 Calcitonin production. Tendency toward local invasion, LNs and haematogenous spread Does NOT respond to I-131
ANAPLASTIC Uncommon Elderly women. Rapid growth and primary lymphatic spread Does NOT respond to I-131
Thyoid mets
Microcalcifications within a node is buzzword. Nodes are typically hyperechoic and hyperenhancing (MRCT). Can bleed lots when mets to brain. Miliary pattern in lung.
Parathyroid anatomy
Normally 4 posterior to gland.
Superior to from 4th branchial pouch, inferior 2 from 3rd branchial pouch. Inferior 2 are more likely to be ectopic.
Parathyroid adenoma
Most common cause of hyperparathyroidism 90%. Look like hypoechoic beans posterior to thyroid. Early enhancement with delayed washout. Sestamibi nuc med scan.
Parathyroid carcinoma
Uncommon. 1% cause of hyperparathyroidism. Looks like an adenoma but may have adenpathy or invasion of adjacent structures.
HYPERPARATHYROIDISM
Hyperfunctioning adenoma 85-90%
Multigland hyperplasia 8-10%
Cancer 1-3%
SESTAMIBI PARATHYROID IMAGING
Depends on mitochondrial density and blood flow.
Useful videos
THYROID CANCERS
https://www.youtube.com/watch?v=f8NILVnxQhU
THYROID DISEASES
https://www.youtube.com/watch?v=Xnd20y97Www
THYROGLOSSAL DUCT CYST
https://www.youtube.com/watch?v=snwEs0u99sY
THYROID EYE DISEASE
https://www.youtube.com/watch?v=WRIbtxk4Zto
HYPERTHYROIDISM
https://www.youtube.com/watch?v=kvyxN12v4mE
