Pheochromocytoma

Definition

Pheochromocytomas are autonomously functioning, catecholamine-secreting, chromaffin-cell neoplasms.

Etiology


About 90% are benign solitary nodules found within the adrenal medulla itself. However, because they can arise any
where neural crest tissue has migrated during the course of embryonic development, approximately 10% are located intra-abdominally in close proximity to the celiac or mesenteric sympathetic ganglia. Adrenal medullary pheochromocytomas are almost always (90%) unilateral. Bilateral lesions usually occur as familial neoplasms, as in type IIa (Sipple's syndrome) or type IIb multiple endocrine neoplasia syndrome (Table 69.5). The multiple endocrine neoplasia syndromes are transmitted as autosomal dominant diseases with incomplete penetrance and variable expression.


Sign And Symptoms

SPELL RELATED
Anxiety and fear of impending death
Diaphoresis
Dyspnea
Epigastric and chest pain
Headache
Hypertension
Nausea and vomiting
Pallor
Palpitation (forceful heartbeat)
Tremor

CHRONIC
Anxiety and fear of impending death
Cold hands and feet
Congestive heart failure—dilated or hypertrophic cardiomyopathy
Constipation
Diaphoresis
Dyspnea
Ectopic hormone secretion–dependent symptoms (e.g., CRH/ACTH, GHRH, PTH-RP, VIP)
Epigastric and chest pain
Fatigue
Fever
General increase in sweating
Grade II to IV retinopathy
Headache
Hyperglycemia
Hypertension
Nausea and vomiting
Orthostatic hypotension
Painless hematuria (associated with urinary bladder paraganglioma)
Pallor
Palpitation (forceful heartbeat)
Tremor
Weight loss

Diagnosis


The most commonly used screening test is a 24-hour urine measurement of catecholamines (norepinephrine and epinephrine) or their metabolites (metanephrine and vanillylmandelic acid).

Note:
(levodopa, tricyclic antidepressants, and decongestants) influence the test results, all medications should be withheld for a minimum of 1 to 2 days

Plasma norepinephrine, another useful screening test in pheochromocytomas, typically exceeds 2,000 pg/mL


Treatment

Surgical Therapy

Pheochromocytoma is almost always cured by surgical excision of the tumor

Medical Therapy

Combined α- and β-adrenergic blockade is one approach to control blood pressure and to prevent intraoperative hypertensive crises. α-Adrenergic blockade should be started 7 to 10 days preoperatively to normalize blood pressure and to expand the contracted blood volume.