Subclinical phaeochromocytoma

Abstract

Phaeochromocytomas and paragangliomas are neural crest-derived tumours. Autopsy studies indicate that relatively large numbers of these tumours remain undiagnosed during life. This may reflect non-specific signs and symptoms and low medical alertness in evaluating the clinical picture or it may reflect a silent clinical presentation - the subclinical phaeochromocytoma. The associated clinical picture depends on the capacity of the tumours to release catecholamines and sometimes biologically active peptides. Hypertension is the hallmark of catecholamine release, but the amount, type and pattern of catecholamine secretion is extremely variable. Some tumours have low or intermittent secretory activity, some produce mainly or solely dopamine, while others very rarely do not synthesize or release any catecholamines (non-secretory or non-functional tumours). Such tumours may present with mild or even absent signs and symptoms of catecholamine excess. Low secretory activity may reflect small tumour size or differences in secretory phenotypes associated with the biochemical and genetic background of the tumours. Tumours due to succinate dehydrogenase subunit B mutations are often subclinical, poorly differentiated, contain low amounts of catecholamines, and are usually malignant at diagnosis. Adrenoceptor desensitization can result in a subclinical presentation, even when catecholamine levels are high. Subclinical phaeochromocytomas are often discovered as incidentalomas during radiological procedures or during routine screening for phaeochromocytoma in carriers of mutations in one of the ten currently identified tumour susceptibility genes. Undiagnosed phaeochromocytomas, whether or not subclinical and even if biologically benign, may cause extremely deleterious consequences or even death, following abrupt release of catecholamines.

Carcinoma-like nonfunctional pheochromocytoma in the right adrenal gland: A case report

“…Scintigraphy using iodine-123 MIBG, which mimics noradrenaline, is generally able to detect PCC (1), but the current case demonstrated negative results. Nonfunctional PCC, which refers to non-secreting PCC in the present study, is known to exist, but is extremely rare (3). Nonfunctional PCC, which may be associated with succinate dehydrogenase subunit B mutations (3), has not yet been clearly defined.…”

“…PCC arises from chromaffin cells in the adrenal medulla and typically produces catecholamines, resulting in characteristic symptoms, including hypertension, hyperglycemia and headaches (1). PCC without symptoms or secretion of catecholamines, which has been generally termed nonfunctional PCC, is extremely rare (3).…”

Severe Ectopic Cushing’s Syndrome Due to ACTH-Secreting Pheochromocytoma

“…This neoplasm may secrete various substances such as somatostatin, enkephalins, calcitonin, vasoactive intestinal peptide, neuropeptide Y, renin, ACTH, PTH, erythropoietin, adrenomedullin, and DOPA in addition to catecholamines. The symptoms manifested by the patients depend on the prevailing secretory products secreted from the tumor [6]. ACTH eventually produced by the tumor stimulates the adrenal cortex to hypersecrete cortisol.…”

“…Final diagnosis was made by immunohistological analysis. Therefore, the tumor was found to secrete ACTH predominantly, explaining the presentation of severe CS instead of a subclinical pheochromocytoma [6].…”

Pheochromocytoma presenting as hyperglycemic hyperosmolar syndrome and unusual fever

“…Different catecholamine secretions from pheochromocytoma have different effects on blood glucose and blood pressure levels [3]. About 40-50 % of patients with pheochromocytomas clinically present as glucose intolerance or DM, which are such common pathologic conditions that they can delay the timely diagnosis of pheochromocytoma.…”