Pheochromocytoma - SUNY Downstate Medical CenterThe incidence of pheochromocytomas among pati對ents...

PHEOCHROMOCYTOMAAnita Chiu, MDKings County Hospital CenterJanuary 13, 2011

www.downstatesurgery.org

Case Presentation 62 year old female from Grenada with

longstanding HTN, DM, CRI Complaints of “palpitations” for years Abdominal US obtained for vague GI

complaints Further imaging done and patient sent

to endocrine 9/2010 Referred to surgery 11/8/2010 after

endocrine workup


Case Presentation PMH:◦ HTN >30 years◦ DM < 1 year

PSH:◦ TAH◦ Tonsillectomy

SH:◦ Ex-smoker, no EtOH◦ Unemployed

FH:◦ HTN – mother◦ Cervical cancer

Meds:Labetalol 200mg bidNifedipine 90mg dailyEnalapril 10mg dailyHCTZ 25mg dailyJanuvia 100mg dailyGlipizide 5mg dailyReported use of

potassium replacements for hypokalemia


Case Presentation BP 165/90 HR 69 Wt: 165 lbs Gen: Middle aged well nourished female Neck: No cervical LAD, no thyromegaly,

mild acanthosis nigrans posterior neck Lungs: CTA b/l Heart: S1 S2 RRR, no M/R/G Abdomen: soft, no masses Ext: no LE edema, + distal pulses Skin: not hirsute


Case Presentation

142

3.6

100

33

33

1.44

148

10.3

Albumin 4.3


Abdominal US

7.6 x 6.4 x 6.3cm heterogenous soft tissue mass seen posterior to pancreatic tail in region of left adrenal mass with no hypervascular flow


CT SCANEnteric contrast only secondary to baseline elevated creatinine


CT SCAN


CT SCANPancreatic tail displaced anteriorly


CT SCAN


CT SCANHeterogenous 7.0x6.5x8.0cm craniocaudalsoft tissue mass arising from left adrenal


CT SCANLeft kidney displaced posteriorly


CT SCAN


MRI


MRILeft adrenal gland lesion 7.3x7.9x6.6cm with areas of enhancement and heterogenous signal (T1/T2) which likely represents hemorrhagic debris


MRI


Case Presentation Aldosterone – 8 ng/mL (<28) Cortisol – 1.08 µg/mL (AM 4-22, PM 3-

16) Testosterone – 33.80 ng/mL (14-76) Estradiol – 21.04 pg/mL (11-69) Renin activity – 1.75 ng/mg/hr (0.25-

5.82) DHEA sulfate – 55.97 µg/mL (0-157) Calcitonin - <2 pg/mL TSH - 1.032mIu/mL (0.35-5.50) T3 uptake - 32.4% (22.5-37) T4 - 7.9 µg/dL (4.5–10.9)


Case Presentation 24 hr urinary catecholamines,

fractionated◦ Total volume 1250 mL◦ Epinephrine 78 mcg/24 hr (2-24)◦ Norepinephrine 106 mcg/24 hr (15-100)◦ Total E+NE 184 mcg/24 hr (26-121)◦ Dopamine 289 mcg/24 hr (52-540)

24 hr urinary metanephrines, fractionated◦ Metanephrine 3165 mcg/24 hr (90-315)◦ Normetanephrine 3128 mcg/24 hr (122-676)◦ Total M+NM 6293 mcg/24 hr (224-832)


Case Presentation Started on phenoxybezamine

preoperatively as an outpatient Advised to keep hydrated Patient already on beta-blocker Surgery cancelled on 2 separate

occasions due to elevated BP, phenoxybenzamine titrated

BP normal on third appearance and patient taken to OR


Case Presentation Elective laparoscopic resection on

12/7/2010 Transabdominal approach Adrenal vein tented against mass but

easily isolated and ligated No BP fluctuations intra- or

postoperatively POD#0-1 – stable, monitored in SICU POD#1 – transferred to floor Patient discharged home on POD#2 on

no BP medications


Pathology

Specimen Chromogranin staining


DISCUSSION

Pheochromocytoma:Diagnosis, Preoperative Management, Treatment


Presentationwww.downstatesurgery.org

Presenter

Presentation Notes

Patients with pheochromocytoma and paraganglioma often present with hypertension that is of new onset, episodic, and persistent or refractory to standard pharmacologic agents. Additionally, more common signs and symptoms include headache, palpitations, and diaphoresis. Other findings may include anxiety, tremor, pallor, flushing, tachycardia, postural hypotension, visual disturbances, heat intolerance, fever, nausea, vomiting, abdominal pain, constipation, polyuria, hematuria (related to a paraganglioma of the bladder), polydypsia, hyperglycemia, and hypercalcemia.16 Patients with pheochromocytomas may be asymptomatic even in the setting of extremely large tumors (50 g) because of their tendency for cystic degeneration (Figure 15-1). It is essential to note that malignant catecholamine-producing tumors have a clinical presentation identical to their benign counterparts. The most common metastatic sites are regional lymph nodes, bone, liver, and lung.17 In the majority of cases, however, pheochromocytoma and paraganglioma are benign tumors. The malignancy rate is approximately 5% to 10% and 15% to 35%, respectively. According to the WHO, malignancy is defined by the presence of metastatic disease rather than by local invasion.1 There is no single histologic feature, including capsular or vascular invasion or cytologic atypia, that solely identifies metastatic potential.1 Other scoring systems have been used, including those developed by Linnoila and coworkers18 in 1990, Thompson19 in 2002, and Kimura and coworkers20 in 2005; however, they have not been routinely implemented. Pheochromocytomas may present as adrenal incidentalomas. Most that are serendipitously discovered in this way are smaller than 3 cm. The incidence of pheochromocytomas among patients who have adrenal incidentalomas is reported to be between 1.5% and 11%.21 A recent multicenter study involving nearly 100 patients who had pheochromocytomas or paragangliomas reported that 40% of tumors were found incidentally.22 In some cases, pheochromocytomas and paragangliomas are not associated with hypertension. One theory has included the desensitization of catecholamine receptors over time because of constant and chronic exposure that then leads to disruption of normal circadian variation in blood pressure.23 In fact, the same authors have reported that up to 40% of patients with pheochromocytoma are asymptomatic and are considered "subclinical."

Formerly known as the…

10% tumor

Familial

Bilateral

Extra-adrenal

Malignant

Bravo EL, Gifford RW Jr. Pheochromocytoma: diagnosis, localization, and management. N Engl J Med 1984;311:1298-1303. Ilias I, Pacak K. A clinical overview of pheochromocytomas/paragangliomas and carcinoid tumors. Nucl Med Biol 2008;35:27-34.


Presenter

Presentation Notes

Pheo – 1886 Arises from adrenal medulla Neuroendocrine tumor Incidence is less than 0.5% in patients with hypertensive symptoms Once called the 10% tumor because it was thought to be 10% familial 10% malignant 10% bilateral 10% extra-adrenal Now reported up to 30% have a hereditary syndrome

Genetics VHL syndrome◦ Autosomal dominant◦ Mutated tumor suppressor gene,

chromosome 3◦ 20 -80% of patients have

pheochromocytomas◦ Typically bilateral, produce norepinephrine

MEN2◦ RET proto-oncogene, chromosome 10◦ Autosomal dominant or spontaneous new

mutations◦ 20-50% of patients have

pheochromocytomas◦ Typically bilateral, produce epinephrine


Presenter

Presentation Notes

VHL – hemangioblastomas in cerebellum, spinal cord, kidney, retina; associated with several pathologies including renal angioma, RCC, pheo MEN2a (Sipple) – medullary thyroid carcinoma associated with pheo in 20-50% of cases, primary hyperparathyroidism MEN2b – medullary thyroid carcinoma associated with pheo in 50% of cases, with marfanoid habitus and with mucosal and digestive ganglioneuromatosis NF1 (von Recklinghausen) – noncancerous lumps all over body, café au lait spots, lisch nodules (iris hamartomas), osseous lesions

Genetics NF1◦ Autosomal dominant◦ Mutated tumor suppressor gene,

chromosome 17◦ 2% of patient have pheochromocytomas

Succinate dehydrogenase mutation◦ 4 SDH genes on different chromosomes

which encode the 4 subunits of mitochondrial complex II linked to electron transport chain and Krebs cycle ◦ Tendency for aggressive extra-adrenal

disease


Presenter

Presentation Notes

VHL – hemangioblastomas in cerebellum, spinal cord, kidney, retina; associated with several pathologies including renal angioma, RCC, pheo MEN2a (Sipple) – medullary thyroid carcinoma associated with pheo in 20-50% of cases, primary hyperparathyroidism MEN2b – medullary thyroid carcinoma associated with pheo in 50% of cases, with marfanoid habitus and with mucosal and digestive ganglioneuromatosis NF1 (von Recklinghausen) – noncancerous lumps all over body, café au lait spots, lisch nodules (iris hamartomas), osseous lesions

ADRENAL GLANDA quick review


Presenter

Presentation Notes

Masses can be derived from the cortex (90% of functioning gland) or medulla (10%) Corticol functioning masses – aldosteronoma,Cushing’s adenoma, adrenocortical carcinoma, rare sex-hormone producing tumors Pheos are derived from the adrenal medulla – composed of chromaffin cells of neuroectodermal origin ZG – sodium regulating, aldosterone production ZF and ZR – cortisol, androgens (DHEA, DHEASulfate, and androstenedione) Overproduction of cortisol –Cushing’s Too much aldosterone – Conn’s Too many catecholelamines – pheo

Diagnosis – Biochemical Tests

Pheochromocytoma

Virilizingor

feminizing tumors

Cushing’s syndrome

Conn’s syndrome


Presenter

Presentation Notes

When a pheochromocytoma or paraganglioma is suspected, it is imperative that functional biochemical studies be performed before any radiologic imaging is done. The diagnosis of this entity is essential because if not identified, it could result in catastrophic consequences such as sudden death or stroke. Testing patients for excessive production of catecholamines should be the initial step in the differential diagnosis. Unfortunately, some of these tests, whether performed via blood or urine sampling, are plagued by false-positive results. Confounding factors include interfering substances and patient comorbidities that lead to inaccuracies. Specifically, levodopa, pseudoephedrine, amphetamines, reserpine, acetaminophen, ethanol, prochlorperazine, tricyclic antidepressants, labetalol, and methylglucamine from iodine-containing contrast media should be avoided when doing an evaluation. Disorders such as acute myocardial infarction, acute stroke, severe congestive heart failure, acute clonidine withdrawal, and acute alcohol withdrawal may also cause falsely elevated catecholamine levels.24 A comprehensive multicenter cohort study involving 214 patients with and 644 patients without pheochromocytoma was performed.25 The investigators compared the sensitivities and specificities of plasma-free metanephrines, plasma catecholamines, urinary fractionated metanephrines, urinary catecholamines, urinary total metanephrines, and vanillylmandelic acid. They reported that plasma-free metanephrine testing was the best initial test for patients being evaluated for pheochromocytoma. Sensitivities ranged from 97% to 99%, and specificities ranged from 82% to 96%. The false-negative plasma-free metanephrine rate was 1.4%, indicating that the probability of missing a pheochromocytoma with this test is extremely rare.25 In patients at low risk for pheochromocytoma or paraganglioma, others recommend urinary total catecholamines and metanephrines as the initial diagnostic test of choice, with plasma levels reserved for patients with a strong family history.26 It is important to note that in general, whereas pheochromocytomas secrete epinephrine, paragangliomas primarily secrete norepinephrine. Phenylethanolamine N-methyltransferase, an enzyme primarily located in the adrenal gland, converts norepinephrine to epinephrine; therefore, patients with extra-adrenal paragangliomas tend to have higher levels of normetanephrine. Tumors associated with VHL produce mostly norepinephrine, and tumors associated with MEN2 produce both epinephrine and norepinephrine. In malignant disease, dopamine is often preferentially secreted because of alterations in catecholamine synthesis. Because pheochromocytomas and paragangliomas are neuroendocrine tumors, serum chromogranin A may also be used as a tumor marker.27 It may be falsely elevated in patients with renal insufficiency, however. The sensitivity is 86%; and the specificity can be as high as 98% when combined with an elevated plasma catecholamine level in patients with normal renal function (patients with creatinine clearance at least 80 mL/min).28

Diagnosis – Biochemical Tests

Urinary metanephrines

Plasma-free metanephrines

Initial evaluation


Diagnosis – Imaging

CT MRI

FDG-PET MIBG

Confirm & Localize


Presenter

Presentation Notes

Computed tomography (CT), magnetic resonance imaging (MRI), and iodine-metaiodobenzylguanidine (MIBG) scintiscan are the most commonly used radiographic imaging modalities for the evaluation of pheochromocytomas and paragangliomas. CT is the anatomic imaging examination of choice in the evaluation of both pheochromocytomas and paragangliomas. The sensitivity of detecting pheochromocytomas measuring at least 0.5 cm in size is approximately 95% to 100%, and the sensitivity of identifying extra-adrenal paragangliomas at least 1.0 cm in size is approximately 90%.29 The specificity, however, is poor and may be as low as 50%.30 For pheochromocytomas, an adrenal protocol-based CT is recommended in which thin-sliced images are obtained before and after injection of intravenous (IV) contrast medium. For small pheochromocytomas that are typically homogenous in appearance, an unenhanced CT scan usually shows a soft tissue density of 40 to 50 Hounsfield units (HU) and uniform enhancement with contrast. Larger pheochromocytomas may undergo cystic degeneration, necrosis, or hemorrhage, causing an inhomogeneous appearance.31 For paragangliomas, if no appreciative mass is identified intraabdominally near the inferior vena cava, abdominal aorta, organ of Zuckerkandl, or bladder, then a CT scan of the neck and chest should be obtained because paragangliomas may be located in the carotid body or mediastinum.32 Because these paragangliomas are mainly derived from chromaffin cells, they have a soft tissue density of 40 to 50 HU. Occasionally, CT scans may not be suitable for the anatomic assessment of pheochromocytomas and paragangliomas. For pregnant women, children, and patients who are allergic to contrast media, MRI may be more appropriate. Classically, MRI scans display increased signal intensity on T2-weighted images attributable to the vascular nature of pheochromocytomas and paragangliomas. However, in large tumors, MRI may depict low signal intensity on T2-weighted images if necrosis or hemorrhage is significant. For the detection of paragangliomas in comparison with pheochromocytomas, MRI has a higher sensitivity (90% to 100%) and a higher specificity (50% to 100%).29 If biochemical studies suggest pheochromocytoma but CT does not localize the tumor, MRI should be used. Another anatomic imaging study that may be used in select settings is ultrasonography. This entity can be initially applicable to paragangliomas of the head and neck such as carotid body tumors, which have characteristic findings of solid, well-defined, hypoechoic lesions with cephalad flow.33 In addition to anatomic imaging, functional imaging can be efficacious in the management of patients with pheochromocytoma and paraganglioma. The more conventional adjuncts include MIBG and fluorodeoxyglucose positron emission tomography (FDG-PET). MIBG should be used when CT or MRI do not identify the adrenal tumor. Additionally, it may be used for paragangliomas as well as for the assessment of recurrent or metastatic pheochromocytoma. MIBG is a norepinephrine analog. In the United States, iodine 131 (131I) is the more commonly used isotope. For pheochromocytomas, the sensitivity of iodine 123 (123I) is 83% to 100% and 131I, 77% to 90%. For paragangliomas, the sensitivities are lower, and the specificity is 95% to 100%.29 Implementing MIBG can be complicated. Patients need to ingest potassium iodide or potassium perchlorate to prevent thyroid uptake that would otherwise obscure paragangliomas of the neck. Recent experiences at the National Institutes of Health suggest that fluorodopamine is an excellent agent to localize adrenal and extra-adrenal tumors, including metastatic lesions.34 Compared with other amines, dopamine is a more specific substrate for the norepinephrine transporter. In some instances, patients with metastases who with negative MIBG results had positive PET results.35 In summary, CT scans should be used first for anatomic imaging for most pheochromocytomas and paragangliomas. If CT is unremarkable, MRI should be used. If available, the functional imaging modality of choice should be FDA-PET. If this test is not available, MIBG should be obtained for paragangliomas and for recurrent or metastatic disease. 98% found in abdomen, 2 % thorax, 1% neck y CT, MRI 87-100% sensitive y I131-MIBG 77-87% sensitive CT and MRI are excellent for delineating the regional anatomy but have poor specificity for identifying pheochromocytomas. In contrast, nuclear scintigraphy using iodine-131 or 123I-metaiodobenzylguanidine (MIBG) has excellent specificity (95% to 100%) while providing information on tumor function. Indications for MIBG scanning have drastically changed over the past 5 years and currently include localization of most cases of biochemically confirmed pheochromocytomas, when an adrenal mass is not identified, or in suspected metastatic disease. 123I-MIBG is preferred over 131I-MIBG because it results in more avid tumor uptake and shorter scan times and can be used in association with single photon emission CT to better identify the tumor. To prevent thyroid ablation when 131I-MIBG is used, thyroid blockade is achieved by oral administration (4 drops) of saturated potassium iodide three times a day for a total of 5 days starting on the day before injection of the radiopharmaceutical. When 123I-MIBG is used, oral administration of saturated potassium iodide can be reduced to three times a day for 3 days. Patients who are allergic to iodine may be given potassium perchlorate three times a day, starting 1 day before injection and continuing for a total of 4 days for 131I-MIBG or 3 days for 123I-MIBG.

Preoperative ManagementDrug Starting Dose Maximum Dose NotesPhenoxybenzamine 10 mg PO BID at time of

diagnosis2 mg/kg/day May increase to 10 mg

PO TID over 10 to 14 days; goal is postural hypotension; nonselective α-blocker

Prazosin 1 mg PO BID at time of diagnosis

15 mg/day May increase to TID dosing; goal is postural hypotension; selective α-blocker

Doxazosin 1 mg PO daily 16 mg/day May increase weekly; at time of diagnosis, goal is postural hypotension; selective α-blocker

Terazosin 1 mg PO qHS at time of diagnosis

20 mg/day May use BID dosing; goal is postural hypotension; selective α-blocker

Verapamil 80 mg PO TID 480 mg/day Calcium channel blocker used for paroxysmal hypertension

Amlodipine 5 mg PO daily 10 mg/day May increase after 1–2 weeks; calcium channel blocker used for paroxysmal


Presenter

Presentation Notes

Although several options exist for the treatment of patients with pheochromocytomas and paragangliomas, the mainstay of treatment is surgical extirpation. Under no circumstances should a patient determined preoperatively to harbor a pheochromocytoma or paraganglioma, undergo a fine-needle aspiration biopsy (FNA). These tumors are highly vascular; furthermore, using FNA may precipitate a hypertensive crisis, hemorrhagic event, or death.36 The management of patients with pheochromocytomas and paragangliomas involves meticulous preoperative, intraoperative, and postoperative care. Patients should be started on -blockade therapy preoperatively, preferably with phenoxybenzamine, an adrenergic inhibitor. Side effects include lightheadedness and sexual dysfunction. Phentolamine, another adrenergic inhibitor, can also be initiated in lieu of phenoxybenzamine. -Blockade therapy should be implemented at least 2 weeks before operative intervention. If the patient develops tachycardia, -blockade should also be added. Medical therapy, including -blockade, should be continued until the morning of surgery. NE and Epi production primarily affect alpha receptors for vasoconstriction Screen with urine metanephrines and VMA Diagnosis usually by CT +screen but no mass, consider venous sampling, then unilateral adrenalectomy 10% bilateral, unless assoc. with MEN II where 70% bilateral=pre-op MIBG

Preoperative Management

Drug Starting Dose Maximum Dose Notes

Nifedipine 30–90 mg PO daily 120 mg/day May increase after 1–2 weeks; calcium channel blocker used for paroxysmal hypertension

Labetalol 100 mg PO BID 2400 mg/day May increase in 100 mg increments every 2–3 days; used after α-blockade for rebound tachycardia with a goal of resting HR 60–80 beats/min; has α-blocking properties

Atenolol 50 mg PO daily 100 mg/day May increase after 7–14 days; used after α-blockade for rebound tachycardia with a goal of resting HR 60–80 beats/min

Metoprolol 50 mg PO BID 450 mg/day May increase dose 50 mg every week; used after α-blockade for rebound tachycardia with a goal of resting HR 60–80 beats/min

Metyrosine 250–750 mg PO QID 4 g/day For refractory hypertension


Presenter

Presentation Notes

Surgical resection is the treatment of choice for pheochromocytoma. However, before surgery, drug treatment is necessary to normalize the blood pressure, the heart rate, and the function of other organs; to restore depleted intravascular volume; and to prevent cardiovascular collapse from surgery-induced catecholamine storm. Adrenergic blockade is needed preoperatively in all pheochromocytoma patients; although there is no standard regimen, β-adrenergic antagonists, dihydropyridine calcium channel blockers, the competitive α- and β-receptor blocker labetalol, and metyrosine have all been successfully used for preoperative adrenergic blockade in patients with pheochromocytoma (Table 2). The selective α1-adrenergic antagonists such as prazosin, doxazosin, and terazosin have the advantage of causing competitive α1-receptor antagonism without rebound tachycardia. At M.D. Anderson Cancer Center (MDACC), we typically begin nonselective alpha blockade at the time of diagnosis using phenoxybenzamine; the starting dosage of 10 mg orally twice daily is gradually increased over 10 to 14 days to 10 mg orally three times daily until effective blockade occurs, as evidenced by the development of postural hypotension or nasal congestion. The total dose should not exceed 2 mg/kg/day. Because of the chronic vasoconstriction experienced by most patients with pheochromocytoma, volume contraction is often present, so liberal salt and fluid intake is encouraged to promote intravascular expansion. With appropriate nonselective α-blockade and restoration of intravascular volume, some patients will experience rebound tachycardia, which can be effectively treated with β-blockade. However, β- blockade should not be initiated before first documenting the efficacy of α-blockade, because a hypertensive crisis may ensue from unopposed α-adrenergic stimulation. This could lead to left-heart strain and congestive heart failure. The goal of β-blockade is a resting heart rate of 60 to 80 beats/min; this can usually be achieved with oral administration of a selective β-blocker such as atenolol or metoprolol (given once or twice daily). Alternatively, labetalol may be given at a starting dose of 100 mg orally twice daily and titrated every 2 to 3 days in 100 mg increments. In cases of refractory hypertension, metyrosine can be added at doses of up to 250 to 750 mg orally every 6 hours. The last oral doses of α- and β-blockers should be administered the morning of surgery.

Resection Open◦ Generally reserved

for larger (>6cm) pheochromocytomasand for paragangliomas in locations that make laparoscopy difficult

Laparoscopic◦ Posterior

retroperitoneoscopicadrenalectomy◦ Transabdominal

laparoscopic adrenalectomy –gold standard◦ Studies advocate

laparoscopic approach even for tumors >6cm

Toniato A, et al. Is the laparoscopic adrenalectomy for pheochromocytomathe best treatment? Surgery. 2007 Jun;141(6):723-7.


Presenter

Presentation Notes

Transabdominal Laparoscopic Adrenalectomy Transabdominal laparoscopic adrenalectomy has been the gold standard for resection of small, solitary, unilateral pheochromocytomas. The procedure is performed with the patient in the lateral decubitus position, with the bed flexed at the patient’s waist to maximize the distance between the iliac crest and ribs. An incision is made approximately 2 cm below and parallel to the costal margin to access the abdominal cavity. Three 10 mm trocars are placed under direct vision along the subcostal region two fingerbreadths below the costal margin. The trocars are equally spaced between the midclavicular line medially (lateral to the border of the rectus abdominis sheath) and the midaxillary line laterally, inferior and posterior to the tip of the eleventh rib. A 30-degree laparoscope is then placed through the middle trocar, and a fourth trocar is placed at the costovertebral subcostal angle, after the peritoneal reflection of the kidney has been dissected. For a right adrenalectomy, the liver is mobilized medially by incising the right lateral hepatic attachments and the triangular ligament. A fan retractor is inserted through the most medial port to retract the liver, but the hepatic flexure of the colon may need to be mobilized for optimal exposure. The adrenal gland is identified at the medial aspect of the superior pole of the kidney. The Gerota fascia is incised, and dissection of the adrenal gland is performed circumferentially. The right adrenal (suprarenal) vein is identified, clipped, and divided. It is important not to avulse this vein from the vena cava. Often, multiple smaller veins are present; these need to be divided between clips, with an EnSeal device or Harmonic scalpel. The arterial branches can be divided using the same techniques. For a left adrenalectomy, the splenic flexure is mobilized medially to move the colon away from the inferior portion of the adrenal and to expose the lienorenal ligament. The lienorenal ligament is incised approximately 1 cm from the spleen, and dissection is carried up to the diaphragm and stopped when the short gastric vessels are encountered behind the stomach. The tail of the pancreas and the spleen are allowed to fall medially to expose the underlying adrenal gland, which is often referred to as the “opening the book” technique. A fan retractor may be used to retract the spleen or kidney in obese patients. The lateral and anterior portions of the adrenal gland are dissected free by first grasping a small amount of periadrenal fat for retraction, leaving the adrenal capsule intact. The dissection can then proceed. The adrenal vein is identified and clipped, with attention to the fact that the vein drains into the left renal vein. The remainder of the dissection proceeds similar to the technique described for right adrenalectomy.

1. LEFT ADRENAL DRAINS INTO LEFT RENAL VEIN2. RIGHT ADRENAL GOES INTO IVC

Remember…


Intraoperative Management

Hypertensive crisis and/or

tachyarrythmia

Acute hypotension

following adrenal vein

ligation


Presenter

Presentation Notes

Intraoperatively, it is essential that the patient has optimal IV access and is monitored hemodynamically because fluctuations in blood pressure are to be expected. Communication with the anesthesiologist is critical, especially when the tumor is manipulated. Venous control of the adrenal vein is important because it limits hemodynamic lability. Postoperatively, patients should be in a monitored setting because they often require norepinephrine to maintain adequate blood pressure. Even with effective preoperative adrenergic blockade, a hypertensive crisis or tachyarrhythmia can occur intraoperatively, as manipulation of the tumor can cause a catecholamine surge. Patients should therefore have adequate peripheral and central venous access catheters, as well as a radial artery catheter, in place. Intravenous, titratable agents to control blood pressure should be premixed and available, should fluctuations in blood pressure occur. The dihydropyridine calcium channel blocker nicardipine, at a concentration of 0.5 to 1.0 mg/mL, and the direct acting vasodilator sodium nitroprusside, at doses of 0.5 to 3 ?g/kg/min, are the agents of choice for rapid control of acute hypertension. Conversely, ligation of the adrenal vein in the case of pheochromocytoma, or of other draining vessels in the case of paraganglioma, can cause abrupt cessation of catecholamine release and subsequent acute hypotension. If hypotension occurs, epinephrine, norepinephrine, or phenylephrine should be administered and titrated, with crystalloids and blood products added as needed.

Postoperative Management 12 to 24 hours postop require

monitoring in a step-down or ICU Laparoscopic resections are usually

discharged home on POD#2 No BP medications on discharge


Presenter

Presentation Notes

For the first 12 to 24 hours after surgery, patients should be monitored closely in a step-down or intensive care unit, because hemodynamic fluctuations can occur. It is important to keep patients well hydrated after resection of a pheochromocytoma, as hypotension is not uncommon. At times, small doses of vasopressors may be needed to maintain normotension. Acute adrenal insufficiency can occur if no functional cortical adrenal tissue remains. Adrenal insufficiency should be treated with hydrocortisone at a dosage of 100 mg intravenously every 8 to 12 hours as needed to maintain vascular tone. Hypoglycemia can also occur postoperatively, so blood glucose should be monitored to allow prompt detection and treatment of this condition. Although some surgeons measure plasma metanephrines immediately after surgery to confirm the absence of residual disease, that is not the practice at MDACC, because normal results at this time do not exclude the presence of microscopic residual disease. Patients who undergo retroperitoneoscopic or transabdominal laparoscopic resection are usually discharged home on postoperative day 2, but those who undergo open resection are discharged upon return of bowel function. Most patients do not need to be prescribed antihypertensive medications at discharge, as blood pressure is usually normal within a few days after surgery. However, hypertension can persist through the postoperative period and into the short-term follow-up period because of the resetting of baroreceptors and altered sensitivity of blood vessel smooth muscle to circulating catecholamines.

Summarywww.downstatesurgery.org

References 1. Bravo EL, Gifford RW Jr. Pheochromocytoma:

diagnosis, localization, and management. N Engl J Med1984;311:1298-1303.

2. Ilias I, Pacak K. A clinical overview of pheochromocytomas/paragangliomas and carcinoidtumors. Nucl Med Biol 2008;35:27-34.

3. Morita S, et al. Chapter 15. Pheochromocytoma and Paraganglioma. McGraw-Hill Manual: Endocrine Surgery, 2008.

4. Silberfein E, Perrier N. Endocrine Glands: Management of Pheochromocytomas. Cameron: Current Surgical Therapy, 10th ed, 2010.

5. Toniato A, et al. Is the laparoscopic adrenalectomy for pheochromocytoma the best treatment? Surgery. 2007 Jun;141(6):723-7.


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