adrenal.pptx

adrenal.pptx

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  Adrenal Anatomy ,Tumours& Workup of Patients Presentation- Vikash Singh Moderator: Dr Palaniappan
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  Anatomy  The adrenalglands are paired retroperitoneal organs composed of  cortex and medulla and located above the kidney.  Gross examination reveals  Cortex- spiculated,mustard yellow coloured  Medulla- central , brown colour  Weight ~ 4-5 gram   Size Length 4-6 cm Width 2-3 cm   Right adrenal is triangular in shape and left adrenal crescent in shape.
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  Relations  The rightand left adrenal glands are located within Gerota fascia at the levels of the 11th and 12th ribs.  Medial aspect of the right adrenal gland is often retrocaval. Right Adrenal Left Adrenal Anteriorly Liver Stomach,Pancreas[body] ,splenic vessels Posteriorly Diaphragm Diaphragm Superiorly Diaphragm Spleen Inferolaterally Rt Kidney Lt Kidney Medially IVC Aorta
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  Surgical anatomy
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  Arterial Supply • 3arterial sources of flow: • Branches from Inferior Phrenic Artery  Superior Adrenal A. • Direct visceral branches from Aorta  Middle Adrenal A. • Branches from I/L Renal Artery  Inferior Adrenal A. The main adrenal arteries  branch to form a subcapsular plexus • From subcapsular plexus • Some branches continue directly  to medulla • Others form sinusoids  to cortex
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  Venous Drainage: • Medullaryveins coalesce to form adrenal vein Right adrenal vein • Short • Drains directly into post IVC Left adrenal vein • Long as compared to right adrenal vein • Joined by Inferior Phrenic vein prior to draining into Left Renal Vein • The overlapping of both arterial and venous anatomy makes partial adrenalectomy possible with little risk of subsequent adrenal infarction
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  Variations in theright adrenal veins
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  Variations in theright adrenal veins
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  Tumors of AdrenalCortex Classified according to  Functional or non functional status  Benign or malignant features Adreno-cortical tumors include-  Aldosteronoma[Conn Syndrome]  Cortisol producing adenoma[Cushing syndrome]  Virilizing/feminizing adrenal tumors  Adrenocortical carcinoma  Adrenal Metastases  Nonfunctioning adrenal tumors[Incidentaloma]
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  Diagnosis  Involves screening,confirmatory testing, and subtype differentiation. Indications for Primary Aldosteronism Screening  Severe hypertension (≥160/≥110)  Hypertension with hypokalemia  Adrenal Incidentaloma with hypertension  Resistant hypertension (three or more oral agents with poor control)  Early-onset hypertension (<20) or stroke (<50 years)  Unexplained hypokalemia (spontaneous or diuretic induced)  Whenever considering Secondary causes of hypertension (i.e., pheochromocytoma or renovascular disease)  Evidence of target organ damage disproportionate to degree of hypertension
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  Screening Test • Priorto screening • Hypokalemia should be corrected • All contraindicated medications to be discontinued • Screening for primary aldosteronism begins by obtaining a morning (between 8 and 10 AM) plasma aldosterone concentration (PAC) and plasma renin activity (PRA) • The National Institutes of Health (NIH) Consensus Statement (2002) on the management of the clinically inapparent adrenal mass suggests cut-offs of • > 30 for ARR [Aldosterone renin ratio] • > 20 ng/dL for PAC • All positive tests must be confirmed with further testing
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  Confirmatory Test Of thepatients with positive screening tests, only 50% to 70% will be diagnosed with PAL on confirmatory testing • Of the confirmatory tests available Following evaluate suppression of aldosterone following sodium loading • Fludrocortisone suppression test • Oral sodium loading test • Intravenous saline infusion test Following evaluate suppression of ARR following administration of an ACE inhibitor. • Captopril suppression test
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  Subtype Differentiation  Subtypedifferentiation of PAL is essential in selecting appropriate therapy, because surgical therapy is only successful for select subtypes  Adrenal CT scan  Radiographic characteristics of aldosterone-producing adenomas  unilateral low-density non-enhancing lesion of less than 10 Hounsfield units (HU)  Average size of 1.6 to 1.8 cm  Normal appearing contralateral adrenal gland.  ~ 20% of aldosterone-producing adenomas = < 1 cm in size. Therefore lateralization is not based on CT findings alone Adrenal MRI  MRI does not offer an advantage in delineating primary aldosteronism subtypes, and is a/w increased cost  Routine use is not currently recommended
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  Lateralisation Studies • To establishlateralization of aldosterone secretion in surgical candidates, adrenal vein sampling should be performed. • Percutaneous access to the femoral vein is obtained, and catheter tips are positioned to collect samples from three sites: the right adrenal vein, left adrenal vein, and inferior vena cava (IVC). • Samples are evaluated for aldosterone and cortisol concentrations. • Lateralization of aldosterone secretion is determined by comparing the aldosterone to cortisol ratios of the dominant to nondominant sides. • Aldosterone is considered to be lateralized if ratio is greater than 2-4 : 1, depending on the use of ACTH stimulation Alternative studies when AVS is inconclusive due to sampling error • Nuclear Scintigraphy • Postural stimulation testing • Measurement of cortisol metabolites
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  Cushing Syndrome  Definition Hypercortisolism secondary to excessive production of glucocorticoids by the adrenal cortex is defined as Cushing syndrome  Incidence: 2 - 5 cases/million people/yr SUBTYPES
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  ACTH-Independent Cushing Syndrome Diagnosis Screening Test:  24-hour Urinary free cortisol  This test is considered the gold standard diagnostic test.  Direct measure of free bioavailable cortisol  Normal cutoff value of 50 mcg/ 24 hr urine volume is used.  Low dose dexamethasone suppression test  Patients take 1 mg of dexamethasone, a synthetic steroid, at 11 pm and cortisol level is measured at 8 am the next day.  In normal patients cortisol should be below 5 mcg/dl.  Late-night salivary cortisol  This is the latest diagnostic test for Cushing’s.  Elevated cortisol levels b/w 11 PM & midnight = earliest indication of disease.  Cortisol level should not exceed 145 ng/dl.  In adrenal tumors ACTH level is low and CT/MRI of the adrenal almost always identifies the tumor.
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  Adreno cortical Carcinoma Itis a rare malignancy with incidence of 0.5 to 2 per million.  Bimodal age distribution,peaks in 1st and 4th -5th decade.  Majority of cases are sporadic and unilateral.  Functional breakdown of ACC Functional 50%-80% Cushing Syndrome 33%-53% Cushing Syndrome + Virilization 20%-24% Virilization alone 10%-20% Feminization 6%-10% Hyperaldosteronism 2.5%-5% Non functional 20%-50%
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  Diagnosis, Functional Evaluation Typeof Adrenal Hypersecretion Functional Evaluation Glucocorticoid excess Low- Dose dexamethasone suppression test Or late night salivary Or 24 hour urinary cortiisol Sexual steroids& steroid precursors DHEA-S 17-OH- Progesterone Androstenedione Testerone 17B – esterediol( only men & post – menopausal women Catecholamine excess Serum or urinary metanephrines Mineralocorticoid excess Aldosterone to renin ratio(in patients with hypertension & hypokalemia
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  Imaging  CT Scan: radiographic characteristics of ACC on CT imaging include  irregular borders, irregular enhancement, calcifications,  necrotic areas with cystic degeneration.  Mean attenuation on noncontrast CT scan in ACC is significantly higher (39 HU) compared with adenomas(8 HU).  No contrast washout  For metastatic evaluation  Lymphadenopathy  Extension to IVC and other adjacent organs.  Distant metastases to lung and liver.  MRI:  ACCs appear isointense relative to the liver or spleen on T1-weighted images and demonstrate intermediate to increased intensity on T2-weighted images.  essential tool in detecting the presence of a tumor clot and delineating its extent.
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  Percutaneous needle biopsy Primaryindication for needle biopsy is in cases of unresectable, locally advanced, or metastatic disease, to confirm the diagnosis prior to systemic medical therapy. In cases of surgically resectable disease, the information obtained from biochemical and radiographic evaluation should be enough to justify extirpation.
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  Treatment Surgery  Approach: Opentransabdominal or retroperitoneal approach is preferred  Complete surgical excision is essential in the management of adrenal cortical carcinomas and offers the best chance of cure.  For locally advanced disease : enbloc resection should be performed, whenever possible.  Cases of venous tumor thrombus involving the IVC may require vascular bypass techniques, IVC replacement, and/or IVC interruption.  In cases of metastatic adrenal carcinoma, cytoreductive removal of the primary tumor and debulking metastatectomy should be considered if greater than 90% of the disease burden can be removed.  In patients who are not candidates for complete tumor debulking, surgery should not be performed because it will delay systemic therapy.  Rate of recurrence – 60-80 % despite aggressive surgical resection.
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  Adrenal Incidentaloma  Adrenalincidentalomas are unsuspected adrenal masses greater than 1 cm in diameter identified on cross sectional imaging performed for seemingly unrelated causes.  It is important to emphasize that “incidental” does not mean “insignificant”.  Incidence : 1-4% patients undergoing abdominal imaging studies.
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  Diagnostic Algorithm
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  Pheochromocytoma  Tumour ofcatecholamine-producing cells of adrenal medulla  Incidence: ~ 1 – 2/1,00,000 individuals  Classically, pheochromocytoma has been called the “10% tumour”: 10% extra-adrenal, 10% familial, 10% bilateral, 10% paediatric, and 10% malignant  However up to 25% of pheochromocytomas can be extraadrenal and upto 30% cases familial.  Tumors arising from the right adrenal are more common, tend to be larger, and recur more frequently than those that arise in the left gland  Pediatric pheochromocytoma is the most frequently encountered endocrine neoplasm in children.
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  Diagnosis  Biochemical Evaluation
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  Pre-operative work up History& exam: • Age and obesity • Is it a functional adrenal mass? • What is the likelihood of malignancy? • Past surgical/medical history - preventing laparoscopy • Primary or recurrence? • Comorbidities like HTN, DM, etc • Consent for Nephrectomy
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  Diagnosis and workup: • Contrasted CT/ MRI (where is the site and what size is it?) CROSS-SECTIONAL IMAGING (CT Scan) • Pheochromocytomas appear as well-circumscribed lesions • Given their rich vascularity and low lipid content, Pheochromocytomas typically measure an attenuation > 10 HU on NCCT (mean ≈35 HU) • Although nonspecific, Pheochromocytomas, unlike adenomas, do not exhibit rapid contrast washout on delayed imaging MRI • Similar to CT, magnetic resonance imaging is an excellent imaging modality for characterizing adrenal lesions • Classically “light bulb” sign is seen which was earlier believed to be diagnostic of pheochromocytoma.
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  Thank You