Association with Multiple Endocrine Neoplasia
In both children and adults, pheochromocytoma can present either as an isolated tumor or as part of familial multiple endocrine adenomatosis (syndromes of multiple endocrine neoplasia).
This condition involves the simultaneous development of functioning tumors in multiple endocrine glands. When pheochromocytoma is part of such a syndrome, the most typical localizations of concurrent neoplasms include:
- The endocrine pancreas (islet cells).
- The parathyroid glands.
Cardiovascular Manifestations
The clinical presentation of pheochromocytoma is directly attributable to catecholamine excess, with the cardiovascular system serving as the primary target.
The hallmark is arterial hypertension, which can present in either sustained or paroxysmal forms. The clinical course is frequently complicated by severe hypertensive crises.
A paradoxical manifestation of hypercatecholaminemia is acute hypotensive reactions accompanied by syncope. These present as orthostatic collapse or the so-called "rebound" syndrome immediately following a hypertensive crisis. Furthermore, the toxic effect of hormone excess on the myocardium triggers various cardiac arrhythmias.
Metabolic and Autonomic Features
Catecholamine excess triggers a pronounced catabolic effect, resulting in systemic metabolic shifts. Patients exhibit progressive weight loss. Blood tests reveal elevated glucose levels (hyperglycemia) and lipids (hyperlipidemia).
Persistent receptor stimulation produces characteristic autonomic symptoms:
- Profuse sweating (hyperhidrosis).
- Tremors.
Long-standing arterial hypertension also leads to specific retinal damage — hypertensive retinopathy.
Laboratory Diagnostics
The cornerstone of laboratory confirmation is the detection of hormone breakdown products. A specific marker of pheochromocytoma is an elevated concentration of urinary catecholamine metabolites.