ADRENAL INCIDENTALOMA Jamii St. Julien
Outline Definition Differential Evaluation Treatment Follow up Questions Case
Definition The phenomenon of detecting an otherwise unsuspected adrenal mass on radiologic imaging Excludes those undergoing imaging for staging/workup for cancer Incidence 8.7%
Outline Definition Differential Evaluation Treatment Follow up Questions Case
Differential Adrenocortical adenoma (60%) Adrenocortical carcinoma (<5%) Cortisol secreting tumor (8%) Pheochromocytoma (5%) Metastatic lesion (2.1%) Aldosteronoma (1%) Ganglioneuroma, myelolipoma, benign cyst, hematoma
Outline Definition Differential Evaluation Treatment Follow up Questions Case
Evaluation 3 questions need to be addressed: Is it hormonally active? Does it look concerning for cancer? Is there a history of prior malignancy?
Evaluation Hormonally Active? Subclinical Cushing s syndrome Determine cortisol excess Overnight dexamethasone (1mg) suppression test 11:00pm Serum cortisol, 8:00am <1.8 µg/dl is normal > 5 µg/dl is diagnostic of SCS Assess adrenal autonomy High dose dexamethasone suppression test Will suppress all but ectopic production
Evaluation Hormonally active? Primary Hyperaldosteronism (Conn s) Initial tests: BMP Biochemical testing indicated if hypertensive or hypokalemic Plasma aldosterone concentration >15ng/dL Plasma renin activity <0.2ng/mL/hr Aldosterone/Renin Ratio >20
Evaluation Hormonically active? Confirmatory Salt loading fails to suppress aldosterone levels
Evaluation Hormonally active? Pheochromocytoma Initial test Fractionated plasma metanephrines Confirmatory 24hr urinary chatecholamines and metabolites
Evaluation - Imaging Goal is to distinguish between adenoma, carcinoma, pheochromocytoma, and metastases. Cannot distinguish between functional and nonfunctional Size <4cm unlikely to be malignant
Hounsfeld units Substance Air Fat HU 1000 120 Water 0 Muscle +40 Contrast +130 Bone +400 or more
Evaluation - Imaging Adenomas High lipid content (typically) Smooth and homogenous Noncontrast CT 10 HU = adenoma Contrast CT (Immediate and delayed (10 min) ) Enhance up to 90 HU, then wash out >50% on delayed scan MRI Low signal intensity on T2-weighted images
Evaluation - Imaging Pheochromocytomas CT (sens 85-95%, spec 70-100%) Enhance to >100 HU Delayed washout of contrast MRI (sens>95%, spec 100%) Appears bright on T2-weighted images 123 I-MIBG (metaiodobenzylguanidine) Useful for localizing extra-adrenal pheos Useful for following pts with malignant pheos Not indicated in uncomplicated pheos localized w/ CT or MRI
Evaluation - Imaging Adrenocortical carcinoma Size >4cm (90% sens, 58% spec) Though most are >6cm on presentation (mean 12-15cm) Irregular contours, heterogenous appearance Invasion, thrombosis CT >10 HU on noncontrast Delayed washout MRI Bright on T2
Evaluation - Imaging Metastases Lung, breast, stomach, kidney, melanoma, lymphoma Heterogenous, irregular Bilateral 10 15% Size 0.8 2.0 cm Cannot differentiate from ACC
Outline Definition Differential Evaluation Treatment Follow up Questions Case
Treatment - Resection Any hyperfunctioning lesion (regardless of size) Any lesion suspected of being malignant due to size or other imaging criteria Solitary metastasis in absence of extra-adrenal disease
Treatment Laparoscopic adrenalectomy 3 approaches Lateral transabdominal Lateral decubitus position Preferred technique by most surgeons Anterior transabdominal Least common. Most difficult exposure No need to change position w/ bilateral Retroperitoneal endoscopic adrenalectomy Appropriate for smaller tumors (<5-6cm) No need to change position with bilateral Good in setting of prior abdominal surgery Advanced skills and experience required
Treatment laparoscopic adrenalectomy Contraindicated Adrenocortical carcinoma Metastatic pheochromocytoma
Treatment specific circumstances Pheochromocytoma α-blockade for 1 3 weeks w/ phenoxybenzamine Until normotensive, orthostatic hypotension, or nasal congestion β-blockade (propranolol) Volume resuscitation Subclinical Cushing s Steroid replacement therapy 6 18 months
Treatment specific circumstances Metastasis ALWAYS rule out pheochromocytoma prior to biopsy or FNA
Outline Definition Differential Evaluation Treatment Follow up Questions Case
Follow up Repeat imaging at 3 to 6 months, then annually for 1 to 2 years. Hormonal evaluation annually for 5 years
Outline Definition Differential Evaluation Treatment Follow up Questions Case
A 50-year-old woman has a 3-cm right adrenal mass discovered incidentally during an abdominal computed tomographic (CT) scan for epigastric pain. She has been healthy since undergoing lumpectomy for stage I breast cancer 7 years previously. The next step should be: 1. measurement of 24-hour urinary cortisol 2. measurement of 24-hour urinary cathecholamine and metabolites 3. CT-guided fine-needle aspiration (FNA) of the mass 4. determination of plasma aldosterone concentration to plasma renin activity ratio 5. operative excision
A 37-year-old hypertensive man has a left-sided 3.4-cm adrenal mass. Initial studies including a 24-hour urine collection for free catecholamine and catecholamine metabolites, an overnight 1-mg dexamethasone suppression test, serum electrolytes, BUN, and creatinine have all been within normal limits. The next diagnostic study should be 1. high-dose dexamethasone suppression test 2. plasma catecholamine determination 3. plasma aldosterone concentration to plasma renin activity ratio determination 4. positron-emission tomography (PET) 5. magnetic resonance imaging (MRI)
Characteristics of adrenocortical carcinoma include all of the following EXCEPT 1. size > 6 cm in diameter 2. estrogen production in 30% of cases 3. irregular shape and irregular margins on computed tomography (CT) 4. biochemically active in two thirds of cases 5. rarely bilateral
Outline Definition Differential Evaluation Treatment Follow up Questions Case
AL - 31yo F w/ abdominal pain CT scan showed 2.2cm left adrenal mass
AL History Some fatigue, difficulty sleeping Exam P: 103 BP: 107/69 Temp: 98.3 deg F Evidence of prior laparoscopic cholecystectomy
AL Biochemical testing 24 hr urinary chatecholamines and metabolites were normal Overnight dexamethasone suppresion test am cortisol level 8.5 High-dose dex supp test also positive Diagnosis?
AL Given choice of resection versus surveillance Left laparoscopic adrenalectomy Path = 2.8cm adrenocortical adenoma Requiring steroid replacement, but otherwise doing well