SSAT ABSITE Review: Endocrine Adrenal, Thyroid, Parathyroid Douglas Cassidy, MD MGH Surgical Education Research and Simulation Fellow @DJCSurgEd https://www.youtube.com/c/surgedvidz 1/22/2020 1 Content Outline • Adrenal: • Parathyroid • Anatomy and Physiology • Anatomy • Incidentalomas • Calcium Homeostasis • Adrenal Cortical Carcinoma • Primary Hyperparathyroidism • Multiple Endocrine Neoplasia • Head and Neck: • Thyroid • Anatomy • Physiology • Neck Dissections • Thyroid Nodules + Ultrasound • Head and Neck Cancers • Thyroid Cancers • Hypo- and Hyper-thyroidism Adrenal Anatomy • Paired RP endocrine glands above superior pole of kidneys • Arterial: • Superior suprarenal from inferior phrenic • Middle suprarenal from abdominal aorta • Inferior suprarenal from renal artery • Venous: • Left adrenal vein drains into the left renal vein • Right adrenal vein drains directly into the IVC Adrenal Incidentalomas: • Evaluation: • Is the mass functioning or non-functioning? • Is the mass benign or malignant? • If malignant, is it primary or secondary? Adrenal Incidentalomas: • Functional Masses: • Adrenal Cortex: • Zona Glomerulosa -- Aldosterone • Zona Fasciculata -- Cortisol • Zona Reticularis -- Androgens • Adrenal Medulla: Catecholamines • Epinephrine / Norepinephrine Aldosteronomas • Function: ↑Na+ absorption and K+ secretion in the distal tubule • ↑H+ excretion in the collecting duct • Labs: ↑Na+, ↓K+, METABOLIC ALKALOSIS • Presentation: uncontrolled / drug- resistant HTN, sxs of low K+ (cramps, weakness) • DDx: • 1°: Adenoma, Hyperplasia, ACC • 2°: renal artery stenosis, cirrhosis, CHF 9 Aldosteronomas • Work-up: • Plasma aldosterone >15ng/dL AND aldosterone : renin ratio ≥ 30 • 1°: ↑PAC, ↓PRA/PAC • 2°: ↑PAC, ↑PRA/PAC • Confirm diagnosis with elevated aldosterone WITH salt loading • Selective venous catheterization --> elevation of aldosterone/cortisol ratio > fourfold (4:1) confirms lateralization • Treatment: • Bilateral hyperplasia --> aldosterone antagonists [spironolactone] • Aldosteronoma --> laparoscopic adrenalectomy 10 Hypercortisolism / Cushing’s Syndrome • Cortisol Function: • Raise blood glucose (directly and indirectly); ANABOLIC in vital organs, CATABOLIC in peripheral tissue • ↑glucagon and ↓insulin-stimulated glucose uptake by cells (insulin resistance) • ↓peripheral protein synthesis and ↑proteolysis [gluconeogenic amino acids to liver] • STIMULATE peripheral lipolysis • Anti-Inflammatory and Immunosuppressive • Presentation: central obesity, moon facies, HTN, polyphagia, polydipsia, easy bruising, muscle wasting/peripheral atrophy, etc. • DDx: • Exogenous steroid use--> MOST COMMON • Pituitary adenomas/hyperplasia (Cushing’s disease; ACTH-producing) **MOST COMMON ENDOGENOUS** • Ectopic ACTH-secreting tumors [small cell lung cancer (SCLC), bronchial carcinoid, thymomas] • ACTH-independent adrenal tumors [adrenal adenomas, adrenocortical carcinomas] 11 Hypercortisolism / Cushing’s Syndrome • Work-up: • Screening: • 24 hr urinary free cortisol –most sensitive/specific test for Cushing’s syndrome • Low-dose Dexamethasone suppression test (1mg at 11PM; measure 8AM cortisol) • Localization and characterizing the disease • Plasma ACTH levels • Low levels (<5 pg/mL) suggest suppression and negative feedback inhibition --> ACTH- independent adrenal tumors • High plasma ACTH levels suggest (non-suppressed) pituitary or ectopic disease • High plasma ACTH ---> HIGH DOSE DEXAMETHASONE SUPPRESSION • No suppression = ectopic disease • Suppression/Partial Suppression = pituitary • Imaging: CT/MRI for localization of adrenal vs. pituitary lesions 12 Hypercortisolism / Cushing’s Syndrome 13 Pheochromocytomas • Synthesis: • Tyrosine is precursor molecule to norepinephrine/epinephrine • PNMT only found in adrenal medulla and organ of Zuckerkandl • COMT and MAO degrade catecholamines Pheochromocytomas • Sxs: non-specific symptoms of catecholamine excess • HTN, headaches, tachycardia, palpitations, sweating • Work-up: • Plasma metanephrines: high sensitivity (97-100%) and ok specificity (85-89%) • Urine 24 hr fractionated and total metanephrines: sensitivity/specificity of 99%/98% • Adrenal CT: HU > 10, retain contrast on CT, no washout [↑ATTENUATION on non-con CT] • MRI: HYPERintense on T2, iso-/hypo-intense to liver on T1 • Unable to localize --> 123 I-metaiodobenzylguanidine (MIBG) scan • MIBG similar to norepinephrine and taken up by adrenergic tissue 15 Pheochromocytoma • Historic “10% rule”: no longer accurate but still useful • 10% malignant --> now 15-20% • 10% familial --> now 25% [MEN2A and 2B, von Hippel-Lindau, NF type 1, hereditary paraganglioma] • 10% extra-adrenal --> most common para-aortic, including organ of Zuckerkandl • Extra-adrenal tumors produce norepinephrine (no PMNT to convert NE to epinephrine) • 10% bilateral • 10% asymptomatic • 10% in children • Treatment: • Pre-op: 2-4 weeks of α-adrenergic blockade [phenoxybenzamine] • Side effects ameliorated with concomitant β-blockade; unopposed α-adrenergic tone if given alone • Pre-op intravascular volume resuscitation [high sodium diet, isotonic IVF] • Intra-op: arterial line for BP monitoring, short acting anti-HTN agents and vasopressor • Post-op: continuous glucose source --> can suffer from severe hypoglycemia 16 Adrenal Incidentalomas Features Adenoma ACC Pheo Mets Size Small (< 3 cm) Large (> 4 cm) Large (> 3 cm) Variable Irregular, Round, clear Shape Smooth, round Irregular unclear margins margins Heterogenous, Heterogenous, Texture Homogenous Heterogenous mixed density mixed density Density > 10 HU < 10 HU > 10 HU > 10 HU (Attenuation) (> 100 HU) Vascularity Not Vascular, Vascular, Vascular, Vascular, (Washout) > 50% washout < 50% washout < 50% washout < 50% washout 17 18 Adrenal Cortical Carcinoma • Presentation: 60% of patients present with symptoms of hormone excess • Glucocorticoids (45%), glucocorticoids + androgen (25%) • More than 40% present with metastatic disease at the time of diagnosis and are not surgical candidates • Rads: heterogeneous with irregular borders and areas of necrosis or hemorrhage • >20 HU (non-con CT) and delayed washout; more than 90% are >6cm on presentation • Avoid biopsy because of potential seeding of tract • Tx: en bloc open adrenalectomy; mitotane for metastatic disease • Most important predictor of survival is adequate resection 20 Thyroid Anatomy/Physiology 21 Diffuse (Graves) Thyroid Nodules Autonomous Single Focus (“Hot”) (Solitary Toxic (HYPERthyroid) Nodule) TSH Heterogenous Radioiodine (Toxic MNG) imaging Hypofunctional Thyroid TSH level Nodule Ultrasound FNA w/ US guidance based on TSH clinical and sonographic features (HYPOthyroid) 22 Hypoechoic Microcalcifications Extrathyroidal Extension Irregular Disrupted Increased Margins Halo sign Vascularity Taller than wide 23 Isoechoic Hyperechoic Mixed solid/cystic Spongiform 24 25 Bethesda Class Percent of FNAs (%) Cancer Risk (%) Workup Non-diagnostic / 5-10% 1-4% Repeat FNA Unsatisfactory Benign 60% 0-3% Clinical Follow-Up Repeat FNA vs. AUS / FLUS 5% 5-15% Molecular Testing Follicular Neoplasm / Molecular Testing Suspicious for a 5% 15-30% + Follicular Neoplasm Diagnostic Lobectomy Suspicious for 5% 60-75% Lobectomy / Malignancy Total Thyroidectomy Lobectomy / Malignant 5% 97-99% Total Thyroidectomy 26 Well Differentiated Thyroid Cancers • Account for 95% of thyroid malignancies • Age is a factor in determination of stage; <45 yo --> stage II is highest stage [**AGE MOST IMPORTANT PROGNOSTIC VARIABLE**] • Younger: stage I = no mets; stage II = metastatic disease • Tumor size, extrathyroidal spread, LN involvement, and metastatic disease all for further classification • in older pts • Stage I: T1N0M0 (<2 cm) • Stage II: T2N0M0 (2-4 cm) • Stage III: T1-3N0-1aM0 [N1a = CENTRAL NODE INVOLVEMENT] • Stage IV: everything else 27 Total Thyroidectomy vs. Lobectomy • Total Thyroidectomy recommended for ANY of the following (NCCN Guidelines for PTC): • Known distant metastases • Tumor >4 cm in diameter • (+) resection margins • Extrathyroidal extension • Cervical nodal metastases • Poorly differentiated histology • Consider: prior XRT or bilateral nodularity • ABSITE: generally total thyroidectomy is procedure of choice if > 1 cm • TT recommended for follicular thyroid carcinoma or Hurthle cell carcinoma • Benefits of a COMPLETION THYROIDECTOMY: • Remove any multifocal tumor • Use of radioiodine to localize any residual thyroid tumor or metastatic disease [residual hemithyroid will light up, rendering this useless] • Ability to use serum thyroglobulin as a surveillance method [residual hemithyroid will produce, rendering this useless] 28 Adjuvant Therapies • RAI Recommendations: patients at high risk of recurrence • Gross extrathyroidal extension • Distant metastases • Primary tumor > 4cm • Post-op unstimulated Tg > 5-10 ng/mL • Lymph Node Dissection: clinically positive and/or biopsy proven nodal metastases ---> formal compartmental dissection • Do not “cherry-pick” nodes / selective dissection • PTC: prophylactic central neck dissection not recommended if clinically (-) 29 Medullary Thyroid Cancer • Derived from parafollicular C cells • Associations: MEN2A and 2B, Familial medullary thyroid carcinoma (FMTC); 20% familial, 80% sporadic • Nonmetastatic MTC should be treated with total thyroidectomy and bilateral central (level VI) neck dissection • No response to RAI: cells do not concentrate iodine • Calcitonin and CEA are tumor markers for MTC • Calcitonin is more sensitive in the detection of MTC recurrence 30 Hypo-/Hyperthyroidism • Hypothyroidism: • Thyroiditis: