pheochromocytoma

Pheochromocytoma

A pheochromocytoma is sometimes malignant tumor disorder. This tumor develops from the chromaffin cells of the adrenal medulla. Not to be confused with the adrenocortical carcinoma (en) which, meanwhile, develops from the cortex of the adrenal gland. It is manifested by severe arterial hypertension.


Epidemiology
This tumor is exceptional, but affects relatively young patients (20-50 years). It affects less than 0.3% of artérielles1 hypertension. Its malignant character is even rarer, but formidable, with the release of liver and bone metastasis.

Historical
His first description goes back to 1886 by Félix Fränkel2 in a deceased patient of what he thought was adrenal gland cancer. The term pheochromocytoma appears in 19123 and corresponds to a particular staining of adrenal tissues after chromate fixation.

Diagnosis
It must be mentioned in front of the symptoms, the imagery finds a adrenal mass. In 10% of the cases we find an extra-adrenal mass, then we talk about Paraganglioma. The definitive diagnosis is Anatomo-pathological.

Clinical
The clinical signs of pheochromocytoma are induced by excessive catecholamine secretion (adrenaline and noradrenaline). This clinical picture includes:

High blood pressure and weight loss
Classically a pallor due to peripheral vasoconstriction
Associated with a typical symptomatic triad (also called "Menard triad" [desired]) but inconstant associating:

Pulsatile headaches;
heart palpitations and tachycardia;
It's a profuse sweat.
Hypertension can be paroxysmal or permanent. Rarely, it may be absent, either because of a hypovolemia, or because of a decrease in concentration of adrénergique4 receptors.

Pheochromocytoma can also be manifested by heart failure on dilated cardiomyopathy. It can also be associated with type II diabetes.

Pheochromocytoma is most often of genetic origin, so it is important to look for elements that may cause suspicion of Von Hippel-Lindau disease, multiple endocrine neoplasia, or neurofibromatosis type 1 or disease of Recklinghausen.

Biology
It is based on the determination of catecholamines and their plasma and urinary metabolites, plasma métanéphrines and Chromogranin, métanéphrine and urinary normetanephrine of 24h, the rate of which is very high. However, the normality of the values does not exclude the diagnosis if the patient has normal blood pressure during the samples.

Associated Genetic anomalies
Search for multiple endocrine neoplasia type 2 (MEN2):
Search for a mutation of the proto-oncogene RET
Search for a hyperparathyroidism
Looking for a medullary thyroid cancer
Search for a mutation of the VHL gene (Von Hippel-Lindau disease)
Neurofibromatosis type 1
Mutation of Genes SDHB, SDHC, SDHD, SDHAF2 or TMEM127
Imaging
The tumor is adrenal in the vast majority of cases but there may exist other locations.

The MIBG (meta-iodobenzylguanidine) scan has a specificity close to 100% but a moindre5 sensitivity.

The Scanner (CT) or MRI thoraco-abdominal allows to detect the tumor secreting with a very good sensitivity but with a lesser specificity.

Treatment
The management of the pheochromocytoma is a highly specialized service of:

The scarcity of this disease
The need for genetic exploration;
The difficulty of surgical management, and in particular the per-operative anesthesia;
The complexity of the therapeutic strategy of malignant forms.
It consists of a surgical ablation of the adrenal gland (adrenalectomy) by laparoscopic pathway in général6. The intervention is sensitive in view of the risk of hypertensive thrust during the procedure. An alpha-and beta-blocker drug preparation helps prevent this risk.