Updated: 10/28/2020

Pheochromocytoma

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Topic
Snapshot
  • A 45-year-old woman presents to the emergency room from her primary care physician’s office for high blood pressure unresponsive to therapy. She has a history of neurofibromatosis type 1, though without any neurological deficits. She has multiple café-au-lait spots on her body. She is found to be hypertensive to 154/121 mmHg. Her 24-hour urine metanephrines and VMA come back elevated. Her abdominal CT comes back with an adrenal mass.
Introduction
  • Nonmalignant tumor of adrenal medulla
    • most common adrenal tumor in adults
      • vs neuroblastoma, which is most common in children
    • secretes catecholamines causing episodic hypertension
  • Pathogenesis
    • chromaffin cells from neural crest origin
  • Epidemiology
    • 40-50 year old
  • Rule of 10’s
    • 10% malignant
    • 10% bilateral
    • 10% extra-adrenal
      • bladder and organ of Zuckerkandl (bifurcation of aorta)
    • 10% calcify
    • 10% kids
  • Associated conditions
    • Von Hippel-Lindau disease
    • MEN 2A
    • MEN 2B
    • Neurofibromatosis type 1
Presentation
  • Symptoms are episodic
    • 5 P’s
      • Pressure (↑ BP)
        Pain (headache)
      • Perspiration
      • Palpitations (tachycardia)
      • Pallor
    • mediated by tumor secretion of epinephrine, norepinephrine, and dopamine
    • therapy-resistant hypertension
  • Physical exam
    • ↑ BP (diastolic)
    • skin hyperpigmentation (café-au-lait spots) may suggest NF1
Evaluation
  • Best initial test 
    • ↑ free metanephrine level in plasma  
  • Confirmation with 24-hour urine collection
    • ↑ vanillyl mandelic acid (breakdown of norepinephrine and epinephrine)
    • ↑ metanephrines (more sensitive than VMA)
  • Histology
    • chromaffin cells with enlarged dysmorphic nuclei
  • Imaging 
    • adrenal mass seen on MRI or CT
    • MIBG scanning
      • nuclear isotope scan to detect extra-adrenal involvement
Differential Diagnosis
  • Functional adrenal tumors
    • various different hormonal syndromes can result, such as
      • Cushing syndrome
        • secondary to unregulated cortisol secretion
      • Conn syndrome
        • secondary to unregulated aldosterone secretion
      • male feminization
        • secondary to unregulated estrogen secretion
      • female virilization
        • secondary to unregulated androgen secretion
          • e.g., androstenedione, DHEA, and testosterone levels 
  • Hyperthyroidism
  • Carcinoid tumors
  • Panic disorder
  • Therapy resistant hypertension from obstructive sleep apnea
Treatment
  • In this sequence of events
    • α-antagonist phenoxybenzamine to prevent unopposed α-action if β receptors are blocked  
    • β-blocker
    • tumor resection
Prognosis, Prevention, and Complications
  • Prognosis
    • very good with resection
  • Complications
    • metastases
      • bones, lungs, and liver
    • transformation to malignant tumor (10%)
    • hypertensive crisis

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(M2.ON.16.4694) A 39-year-old woman, with a history of thyroidectomy and primary hyperparathyroidism presents for surgical evaluation for a right adrenal mass. Preoperatively, which of the following medications should she receive to prevent a hypertensive emergency intraoperatively?

QID: 107708
1

Atenolol

50%

(2/4)

2

Labetolol

25%

(1/4)

3

Lisinopril

0%

(0/4)

4

Nifedipine

0%

(0/4)

5

Phenoxybenzamine

25%

(1/4)

M 7 D

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(M2.ON.15.45) A 43-year-old male with a history of thyroid cancer status post total thyroidectomy presents to his primary care physician after repeated bouts of headaches. His headaches are preceded by periods of anxiety, palpitations, and sweating. The patient says he is unable to pinpoint any precipitating factors and instead says the events occur without warning. Of note, the patient's father and uncle also have a history of thyroid cancer. On exam his vitals are: T 36.8 HR 87, BP 135/93, RR 14, and O2 Sat 100% on room air. The patient's TSH is within normal limits, and he reports taking his levothyroxine as prescribed. What is the next best step in diagnosing this patient's chief complaint?

QID: 104370
1

Abdominal CT scan with and without IV contrast

21%

(4/19)

2

24-hour urine free cortisol

0%

(0/19)

3

High dose dexamethasone suppression test

0%

(0/19)

4

Plasma fractionated metanephrines

63%

(12/19)

5

Plasma aldosterone/renin ratio

5%

(1/19)

M 6 E

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Evidence (2)
EXPERT COMMENTS (5)
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