Correlation Between Plasma Catecholamines, Weight, and Diabetes in Pheochromocytoma and Paraganglioma

Main mechanisms and clinical implications of alterations in energy expenditure state among patients with pheochromocytoma and paraganglioma: A review

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine tumors with diverse clinical presentations. Alterations in energy expenditure state are commonly observed in patients with PPGL. However, the reported prevalence of hypermetabolism varies significantly and the underlying mechanisms and implications of this presentation have not been well elucidated. This review discusses and analyzes the factors that contribute to energy consumption. Elevated catecholamine levels in patients can significantly affect substance and energy metabolism. Additionally, changes in the activation of brown adipose tissue (BAT), inflammation, and the inherent energy demands of the tumor can contribute to increased resting energy expenditure (REE) and other energy metabolism indicators. The PPGL biomarker, chromogranin A (CgA), and its fragments also influence energy metabolism. Chronic hypermetabolic states may be detrimental to these patients, with surgical tumor removal remaining the primary therapeutic intervention. The high energy expenditure of PPGL has not received the attention it deserves, and an accurate assessment of energy metabolism is the cornerstone for an adequate understanding and treatment of the disease.

Ectopic adrenocorticotropic hormone-secreting pheochromocytoma with severe metabolic disturbances: A case report

INTRODUCTION

The occurrence of hypercortisolism resulting from adrenocorticotropic hormone (ACTH)-secreting pheochromocytoma is exceedingly uncommon, with limited documented instances thus far.

PRESENTATION OF CASE

We present a case of ectopic ACTH-secreting pheochromocytoma in a patient who suffered from severe metabolic disorders. Our clinical case outlines the diagnostic history, preoperative correction of the patient's metabolic disturbances and surgical strategy for management of a rare ectopic ACTH producing pheochromocytoma.

DISCUSSION

Ectopic adrenocorticotropic hormone-secreting pheochromocytoma displays multifaceted clinical features and requires prompt diagnosis and multidisciplinary management in order to overcome the related severe clinical derangements.

CONCLUSION

The combination of biochemical and hormonal testing and imaging procedures is mandatory for the diagnosis of ectopic ACTH secretion, and in the presence of an adrenal mass, the possibility of an ACTH-secreting pheochromocytoma should be taken into account.

Pheochromocytoma With High Adrenocorticotropic Hormone Production Capacity Without Pigmentation and Cushingoid Symptoms: A Case Report With a Literature Review

Pheochromocytoma or paraganglioma (PPGL) originating from chromaffin cells can produce diverse hormones in addition to catecholamines, including adrenocorticotropic hormone (ACTH). In pheochromocytoma, high levels of ACTH might not result in pigmentation as typically observed in Addison's disease, and patients might not exhibit the symptoms of Cushing's syndrome, despite ACTH-dependent hypercortisolism. A 63-year-old male patient with hypertension was admitted to our facility, and computed tomography (CT) revealed a large right adrenal tumor. Despite high plasma ACTH (700-1300 pg/mL) and serum cortisol (90-100 µg/dL) levels, no physical pigmentation or Cushingoid symptoms were observed. Urinary metanephrine and normetanephrine levels reached as high as 16.0 mg and 3.2 mg, respectively. 123I-metaiodobenzylguanidine (MIBG) scintigraphy was negative. Low-dose dexamethasone paradoxically increased ACTH and cortisol levels, indicating the potential positive feedback regulation of both hormones by glucocorticoids. The patient was diagnosed with an ACTH-producing pheochromocytoma and underwent successful laparoscopic surgery to remove the adrenal tumor under the intravenous administration of a high-dose α-blocker and hydrocortisone. The levels of ACTH, cortisol, and urinary metanephrine/normetanephrine returned close to normal after tumor removal. We report a rare case of pheochromocytoma with extremely high ACTH/cortisol production but without pigmentation or Cushingoid symptoms. We also reviewed previous reports of ACTH-producing PPGL regarding the paradoxical regulation of ACTH/cortisol by glucocorticoids, pigmentation, Cushingoid symptoms, and negativity of 123I-MIBG scintigraphy.

Secondary diabetes mellitus in pheochromocytomas and paragangliomas

Secondary diabetes mellitus (DM) in secretory pheochromocytomas and paragangliomas (PPGLs) is encountered in up to 50% of cases, with its presentation ranging from mild, insulin resistant forms to profound insulin deficiency states, such as diabetic ketoacidosis and hyperglycemic hyperosmolar state. PPGLs represent hypermetabolic states, in which adrenaline and noradrenaline induce insulin resistance in target tissues characterized by aerobic glycolysis, excessive lipolysis, altered adipokine expression, subclinical inflammation, as well as enhanced gluconeogenesis and glucogenolysis. These effects are mediated both directly, upon adrenergic receptor stimulation, and indirectly, via increased glucagon secretion. Impaired insulin secretion is the principal pathogenetic mechanism of secondary DM in this setting; yet, this is relevant for tumors with adrenergic phenotype, arising from direct inhibitory actions in beta pancreatic cells and incretin effect impairment. In contrast, insulin secretion might be enhanced in tumors with noradrenergic phenotype. This dimorphic effect might correspond to two distinct glycemic phenotypes, with predominant insulin resistance and insulin deficiency respectively. Secondary DM improves substantially post-surgery, with up to 80% remission rate. The fact that surgical treatment of PPGLs restores insulin sensitivity and secretion at greater extent compared to alpha and beta blockade, implies the existence of further, non-adrenergic mechanisms, possibly involving other hormonal co-secretion by these tumors. DM management in PPGLs is scarcely studied. The efficacy and safety of newer anti-diabetic medications, such as glucagon-like peptide 1 receptor agonists and sodium glucose cotransporter 2 inhibitors (SGLT2is), as well as potential disease-modifying roles of metformin and SGLT2is warrant further investigation in future studies.

Pathophysiology and Management of Glycemic Alterations before and after Surgery for Pheochromocytoma and Paraganglioma

Glycemic alterations are frequent in patients with pheochromocytoma and paraganglioma (PPGL), but the real incidence of secondary diabetes mellitus (DM) is uncertain, because prospective multicenter studies on this topic are lacking in the literature. The main pathophysiological mechanisms of glucose homeostasis alterations in PPGL, related to catecholamine hypersecretion, are impaired insulin and glucagon-like peptide type 1 (GLP-1) secretion and increased insulin resistance. Moreover, it has been reported that different pathways leading to glucose intolerance may be related to the secretory phenotype of the chromaffin tumor. Predictive factors for the development of glucose intolerance in PPGL patients are a higher age at diagnosis, the need for a higher number of anti-hypertensive drugs, and the presence of secreting neoplasms. Tumor resection is strongly related to the resolution of DM in PPGL patients, with a significant improvement of glycemic control in most cases. We can hypothesize a different personalized therapeutic approach based on the secretory phenotype. The adrenergic phenotype is more closely related to reduced insulin secretion, so insulin therapy may be required. On the other hand, the noradrenergic phenotype mainly acts by increasing insulin resistance and, therefore, insulin-sensitizing antidiabetic agents can find a greater application. Regarding GLP-1 receptor agonists, the data suggest a possible promising therapeutic effect, based on the assumption that GLP-1 secretion is impaired in patients with PPGL. The principal predictors of remission of glycemic alterations after surgery for PPGL are a lower preoperative body mass index (BMI), a larger tumor, higher preoperative catecholamine levels, and a shorter duration of the disease (under three years). Otherwise, after resection of PPGL, hypoglycemia can occur as the result of an excessive rebound of preoperative hyperinsulinemia. It is a rare, but potentially severe complication reported in a lot of case reports and a few small retrospective studies. Higher 24-h urinary metanephrine levels, longer operative times and larger tumors are predictive factors for hypoglycemia in this setting. In conclusion, alterations of carbohydrate metabolism are clinically relevant manifestations of PPGL before and after surgery, but there is the need to conduct multicenter prospective studies to obtain an adequate sample size, and to allow the creation of shared strategies for the clinical management of these potentially severe manifestations of PPGL.

Unexplained Cachexia as a Presenting Symptom of Pheochromocytoma in a Geriatric Patient

Pheochromocytomas are rare neuroendocrine tumors that may secrete catecholamines, resulting in a wide array of clinical symptoms. While patients classically present with hypertension, headache, diaphoresis, and flushing, these symptoms are present in only 40% of cases. Here, we describe a 70-year-old woman whose predominant symptom was unexplained severe weight loss over a 12-month period associated with fatigue, anxiety, and palpitations at her endocrinologist and geriatrician visits. Diagnostic imaging was performed to assess for malignancy and demonstrated a 2.0 cm × 2.0 cm left adrenal mass. The diagnosis of pheochromocytoma was confirmed by elevated plasma normetanephrine levels. After a 2-week alpha blockade with doxazosin, the patient underwent robotic left adrenalectomy. Following surgery, the patient regained weight, and her hypertension also improved significantly. We hope this uncommon clinical presentation in an older adult characterized by weight loss and frailty will increase the awareness of atypical pheochromocytoma symptomatology, particularly in older individuals.

Glycemic disorders in patients with pheochromocytomas and sympathetic paragangliomas

The objective of our study was to determine the prevalence of glycemic disorders (diabetes mellitus and prediabetes) in patients with pheochromocytomas and sympathetic paragangliomas (PPGLs) and identify risk factors for their development and the likelihood of their resolution after surgery. A multicentric retrospective study of patients with PPGLs submitted to surgery between 2000 and 2021 in 17 Spanish hospitals was performed. Diabetes-specific data were collected at diagnosis, in the immediate- and long-term postsurgical follow-up. A total of 229 patients with PPGLs were included (218 with pheochromocytomas and 11 with sympathetic paragangliomas). Before surgery, glycemic disorders were diagnosed in 35.4% of the patients (n = 81): 54 with diabetes and 27 with prediabetes. The variables independently associated with a higher risk of glycemic disorders were sporadic PPGL (odds ratio (OR) = 3.26 (1.14-9.36)) and hypertension (OR = 3.14 (1.09-9.01)). A significant decrease in fasting plasma glucose and HbA1c levels was observed after surgery, in the short-term and long-term follow-up (P < 0.001). After a median follow-up of 48.5 months (range 3.3-168.9), after surgery, 52% of diabetic and 68% of prediabetic patients experienced a complete resolution. Lower body mass index (BMI) (P = 0.001), lower glucose levels (P = 0.047) and shorter duration of diabetes prior to surgery (P = 0.021) were associated with a higher probability of diabetes resolution. In conclusion, glycemic disorders in patients with PPGLs are present in more than a third of them at diagnosis. Sporadic PPGLs and hypertension are risk factors for their development. More than 50% of cases experience a complete resolution of the glycemic disorder after resection of the PPGLs.

The Clinical Characteristics of Pheochromocytomas and Paragangliomas with Negative Catecholamines

Pheochromocytomas and paragangliomas (PPGLs) associated with negative catecholamines are not uncommon. However, few studies have examined clinical features of patients with these tumors. In the absence of available data, it is difficult to identify characteristics of patients with potential PPGLs and normal serum and urine screens. Therefore, an analysis of patients with PPGLs was conducted retrospectively to compare the clinical features of patients with positive and negative catecholamines. This study included 214 patients, including 69 patients with negative catecholamines. Prevalence rates of diabetes (p < 0.001) and hypertension (p < 0.001) were lower and tumor diameter (p < 0.001) was smaller in the negative-catecholamine group compared with the positive-catecholamine group. Multivariable logistic regression analysis showed that extra-adrenal PPGLs were independently positively associated with negative catecholamines (p = 0.004); hypertension (p = 0.001) and tumor diameter (p = 0.016) were independently negatively associated with negative catecholamines. There was no significant difference in tumor recurrence between the two groups (mean follow-up, 20.54 ± 11.83 months) (p = 0.44). The results demonstrated that PPGL patients with negative catecholamines were more likely to have extra-adrenal tumors and less likely to have comorbidities, and these patients should also be closely monitored for tumor recurrence.

Case Report: Giant Paraganglioma of the Skull Base With Two Somatic Mutations in SDHB and PTEN Genes

Head and neck paragangliomas (HNPGLs) are neuroendocrine tumors. They arise from the parasympathetic ganglia and can be either sporadic or due to hereditary syndromes (up to 40%). Most HNPGLs do not produce significant amounts of catecholamines. We report a case of a giant paraganglioma of the skull base with an unusually severe presentation secondary to excessive release of norepinephrine, with a good outcome considering the severity of disease. A 39-year-old Caucasian woman with no prior medical history was found unconscious and emaciated in her home. In the intensive care unit (ICU) the patient was treated for multi-organ failure with multiple complications and difficulties in stabilizing her blood pressure with values up to 246/146 mmHg. She was hospitalized in the ICU for 72 days and on the 31^st day clinical assessment revealed jugular foramen syndrome and paralysis of the right n. facialis. A brain MRI confirmed a right-sided tumor of the skull base of 93.553 cm³. Blood tests showed high amounts of normetanephrine (35.1-45.4 nmol/L, ref <1.09 nmol/L) and a tumor biopsy confirmed the diagnosis of a paraganglioma. Phenoxybenzamine and Labetalol were used in high doses ((Dibenyline^®, 90 mg x 3 daily) and labetalol (Trandate^®, 200 + 300 + 300 mg daily) to stabilize blood pressure. The patient underwent two tumor embolization procedures before total tumor resection on day 243. Normetanephrine and blood pressure normalized after surgery (0.77 nmol/L, ref: < 1.09 nmol/L). The damage to the cranial nerve was permanent. Our patient was comprehensively examined for germline predisposition to PPGLs, however we did not identify any causal aberrations. A somatic deletion and loss of heterozygosity (LOH) of the short arm (p) of chromosome 1 (including SDHB) and p of chromosome 11 was found. Analysis showed an SDHB (c.565T>G, p.C189G) and PTEN (c.834C>G, p.F278L) missense mutation in tumor DNA. The patient made a remarkable recovery except for neurological deficits after intensive multidisciplinary treatment and rehabilitation. This case demonstrates the necessity for an early tertiary center approach with a multidisciplinary expert team and highlights the efficacy of the correct treatment with alpha-blockade.

A case of pheochromocytoma associated with liver abscess and intestinal pseudo-obstruction

Pheochromocytomas can present with various symptoms. Nonspecific manifestations of pheochromocytoma include intestinal pseudo-obstruction and weight loss. Here, we present a case of pheochromocytoma in which prolonged intestinal pseudo-obstruction due to excess catecholamines was one of the factors leading to the development of a liver abscess. An 18-year-old male patient with a history of status epilepticus and severe intellectual disability was transferred to our hospital for a thorough examination of fever and constipation that had lasted for 2 months. When admitted to our hospital, he had fever, and his body mass index was 9.5 kg/m². Upon comprehensive examination of the patient's fever, the blood culture was found positive for Bacteroides. Computed tomography showed findings of intestinal pseudo-obstruction and a low density region in the liver that indicated a liver abscess. Imaging studies also revealed a right adrenal mass and endocrinological test showed elevated plasma norepinephrine and urine normetanephrine levels. In addition, the right adrenal mass showed uptake on ¹²³I-metaiodobenzylguanidine scintigraphy. These findings led to a definite diagnosis of pheochromocytoma. The patient was eventually diagnosed with a pheochromocytoma coexisting with a liver abscess. After treating the liver abscess with antibiotics and ultrasound-guided drainage, an adrenalectomy was performed. The pathological findings were consistent with pheochromocytoma. Postoperatively, the catecholamine excess normalized and intestinal pseudo-obstruction and weight loss improved. We suspected that prolonged intestinal pseudo-obstruction resulted in bacterial translocation and development of a liver abscess. To the best of our knowledge, this is the first report of a pheochromocytoma associated with a liver abscess. Moreover, the clinical presentation of this patient was unusual for pheochromocytoma, as the patient did not have typical symptoms such as hypertension or tachycardia, but rather presented with constipation, intestinal pseudo-obstruction, and weight loss. This case provides valuable insight regarding the impact of catecholamine excess on the intestinal tract and body weight.