Endocrine MR. Jan 30, 2015 Michael LaFata, MD

Transcription

1 Endocrine MR Jan 30, 2015 Michael LaFata, MD

2 Brief case 55-year-old female in ED PMH: HTN, DM2, HLD, GERD CC: Epigastric/LUQ abdominal pain, N/V x2 days AF, HR 103, BP 155/85, room air CMP: Na 133, K 3.6, Cr 1.4 (baseline 0.7) CBC: wnl Lipase: 600 Admitted and treated for acute pancreatitis with IVF and pain control, d/c in stable condition Btw, pt had CT Abd in ED prior to admission

3 AIM clinic follow up Discharge summary: Specific issues for PCP: CT abd showed 1.5 cm right adrenal mass, pt to follow with PCP re: incidentaloma Pt feeling fine after discharge, no current complaints Doc, they told me I have a tumor above my kidney but not to worry!

4 Next step? No further work-up, obviously benign? Repeat CT in 6 months? Lab requisition? Biopsy (FNA)? Surgical resection?

5 Adrenal incidentaloma Mass lesion > 1 cm in diameter Coincidentally discovered on imaging Without clinical symptoms or suspicion

6 2 important questions What do we want to know? Is it malignant? Is it functioning?

7 3 types of functioning? Cushing s syndrome (subclinical) Cortisol Pheochromocytoma Catecholamines (epi/norepi) Aldosteronoma Aldosterone

8 Prevalence Increasing with better imaging Study , 61k pts, 0.4% 2006 study, 520 pts had CT chest to screen for lung cancer, 4.4% Increases with age 0.2% at ages % at age > 70 More common in DM, HTN, obese Malignancy uncommon

9 Incidence of causes of incidentaloma 80% nonfunctioning adenoma ~5% subclinical Cushing s syndrome ~5% pheochromocytoma <5% adrenocortical carcinoma ~3% metastatic ~1% aldosteronoma

10 Is it malignant?

11 Size Predictive of malignancy Study of 887 pts with AIs from the National Italian Study Group on Adrenal Tumors Adrenocortical Ca > 4cm in 90% 76% of masses > 4cm were benign

12 Imaging phenotype Adenomas are lipid rich On CT, Hounsfield scale Measures attenuation (density) Fat results in low attenuation If <10 HU, likelihood of benign adenoma ~100% Delayed contrast-enhanced CT Adenomas typically exhibit rapid contrast washout Similar pattern with MRI and gadolinium

13 Sir Godfrey Newbold Hounsfield

14 Adrenocortical Adenoma Adrenocortical Carcinoma Pheochromocytoma Metastasis Diameter Usually 3 cm Usually > 4 cm Usually > 3 cm Frequently < 3 cm Shape Round or oval Irregular Round or oval Oval or irregular Margins Smooth Unclear Clear Unclear Texture Homogenous Heterogeneous, with mixed densities Heterogeneous, with cystic areas Heterogeneous, with mixed densities, occasional cystic areas Laterality Usually solitary, unilateral Usually solitary, unilateral Usually solitary, unilateral Often bilateral Attenuation on unenhanced CT Vascularity on contrastenhanced CT Washout of contrast medium at 10 minutes 10 HU > 10 HU (usually > 25 HU) > 10 HU (usually > 25 HU) > 10 HU (usually > 25 HU) Not highly vascular Usually vascular Usually vascular Usually vascular 50% < 50% < 50% < 50% Appearance compared to liver on T 2 -weighted MRI Isointense Hyperintense Markedly hyperintense Hyperintense Necrosis, hemorrhage, or calcifications Rare Common Hemorrhage common Occasional hemorrhage Annual growth rate Usually < 1 cm Usually > 2 cm Usually cm Variable Abbreviations: CT, computed tomography; HU, Hounsfield unit; MRI, magnetic resonance imaging.

15 FNA biopsy? Cytology from FNA sample cannot distinguish benign from malignant adrenal mass Can distinguish between adrenal vs metastatic Should not be done unless pheochromocytoma has been ruled out why? Risk of hemorrhage and HTN crisis

16 Is it functioning? Is it secreting hormone?

17 Hormone evaluation Most are non-functional 10-15% secrete excess hormone What hormones?

18 Hormone evaluation (subclinical) Cushing s syndrome Most frequent hormonal abnormality Pheochromocytoma Hyperaldosteronism

19 Subclinical Cushing s syndrome Lack usual stigmata of overt Cushing s May have 1 or more effect of cortisol secretion Hypertension, DM, dyslipidemia, atherosclerosis, increased incidence of fractures What initial test? 1 mg overnight dexamethasone suppression test 8AM serum cortisol >5 mcg/dl

20 Pheochromocytoma ~3% of AIs Not necessarily symptomatic What test? Plasma metanephrines (simplest) Or 24 hour urinary fractionated metanephrines Differing recs - Screen every patient for pheo?

21 Aldosteronoma Rare, <1% of AIs Hypertensive, hypokalemia Many pts w/ 1 hyperaldo not hypokalemic What test? Plasma aldosterone and renin level Aldosterone-to-renin ratio ARR > 20 24hr urine w/ salt loading (confirms) Other option is salt load & measure aldosterone

22 Treatment

23 Unilateral adrenal masses Clinical scenario & pt age significant factors Suspicious imaging phenotype or size >4cm Consider resection due to c/f adrenocortical Ca

24 Unilateral adrenal masses Pheo: resection SCS: limit surgical resection to pt w/ worsening HTN, glucose tol, dyslipidemia, osteoporosis Cushing s synd: resection Glucocorticoid replacement until HPA recovery 1 hyperaldo: resection

25 Bilateral adrenal masses Pheo: resection SCS:? Similar recs for unilateral mass 1 hyperaldo : spironolactone *pheo must be ruled out prior to resection (and/or biopsy) of any adrenal mass

26 Pheochromocytoma resection What must be given pre-operatively? Alpha blockade Reduce risk of hemodynamic instability

27 Follow up

28 Interval imaging No prospective studies of optimal frequency and duration of follow up for AIs Differing recommendations

29 American College of Radiology For benign appearing mass: No additional workup or follow-up For non-diagnostic imaging features and stable for > 1 year Benign, no further imaging follow-up

30 American Association of Clinical Endocrinologists & American Association of Endocrine Surgeons For all adrenal tumors: Hormonal evaluation at time of dx and then annually x5 years If no surgical resection, re-eval w/ imaging in 3-6 months, then annually for 1-2 years After pheo resection, 10-15% may recur Requires long term follow-up

31 Key Points

32 Key Points >1 cm, coincidentally discovered Most are adenomas Should be evaluated for: Hypercortisolism Hyperaldosteronism Pheochromocytoma Malignancy

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34 Key points Test for hypercortisolism: 1 mg overnight DST Test for pheo: Plasma metanephrines Test for hyperaldo: Plasma renin & aldosterone (ratio >20)

35 Key points If < 10 HU on CT, suggests adenoma Size > 4 cm concerning for malignancy Mass with concerning radiographic characteristics resection

36 Key points For pheo resection with pre-op alpha block For unilateral Cushing s resection Replace glucocorticoid until HPA axis recovery For unilateral hyperaldo resection For bilateral hyperaldo spironolactone

37 Key points Follow-up recommendations variable AACE/AAES more aggressive ACR more conservative

38 References UpToDate, The Adrenal Incidentaloma DynaMed, Adrenal Incidentaloma Evaluation AACE/AAES Adrenal Incidentaloma Guidelines, Endocrine Practice. 2009; 15 (Suppl 1).