It is well known that most pheos in the adrenal glands are functional in that they produce excess catecholamines. About half of paras are functional and the other half non-functional in this sense. Whether a non-functional para can turn into a functional one is not clear.
Functional transformation (from a non-functional tumor to a functional tumor) is well known in other neuroendocrine tumors. To be clear, pheos are a subtype of neuroendocrine tumors. For example, a non-functional pancreatic neuroendocrine tumor can suddenly produce a myriad of hormones, causing ectopic Cushing’s syndrome, hypoglycemia, or hypercalcemia.
A case report is just published describing a young man with cyanotic congenital heart disease who has a para that was initially not functional. In a matter of a few years, the para grew in size and began to produce large amounts of catecholamines, even resulting in cardiomyopathy. The patient’s heart function recovered well after the para was removed. The case report reviews the literature and finds 2 precedent cases. In all three cases including the one just published, the functional transformation is associated with either tumor growth or metastasis.
Pheo functional transformation is thus possible and should be suspected when new symptoms arise.
Dr. Pheo
