A pediatric case of pheochromocytoma without apparent hypertension associated with von Hippel-Lindau disease

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.

Biochemical Diagnosis of Catecholamine-Producing Tumors of Childhood: Neuroblastoma, Pheochromocytoma and Paraganglioma

Catecholamine-producing tumors of childhood include most notably neuroblastoma, but also pheochromocytoma and paraganglioma (PPGL). Diagnosis of the former depends largely on biopsy-dependent histopathology, but this is contraindicated in PPGL where diagnosis depends crucially on biochemical tests of catecholamine excess. Such tests retain some importance in neuroblastoma though continue to largely rely on measurements of homovanillic acid (HVA) and vanillylmandelic acid (VMA), which are no longer recommended for PPGL. For PPGL, urinary or plasma metanephrines are the recommended most accurate tests. Addition of methoxytyramine to the plasma panel is particularly useful to identify dopamine-producing tumors and combined with normetanephrine also shows superior diagnostic performance over HVA and VMA for neuroblastoma. While use of metanephrines and methoxytyramine for diagnosis of PPGL in adults is established, there are numerous pitfalls for use of these tests in children. The establishment of pediatric reference intervals is particularly difficult and complicated by dynamic changes in metabolites during childhood, especially in infants for both plasma and urinary measurements, and extending to adolescence for urinary measurements. Interpretation of test results is further complicated in children by difficulties in following recommended preanalytical precautions. Due to this, the slow growing nature of PPGL and neglected consideration of the tumors in childhood the true pediatric prevalence of PPGL is likely underappreciated. Earlier identification of disease, as facilitated by surveillance programs, may uncover the true prevalence and improve therapeutic outcomes of childhood PPGL. For neuroblastoma there remain considerable obstacles in moving from entrenched to more accurate tests of catecholamine excess.

Biochemically normal adrenal pheochromocytoma following extensive central necrosis in a child with von Hippel-Lindau (VHL) gene mutation

Pheochromocytomas are rare in children. The diagnosis is usually established from a raised urinary or plasma catecholamine or their metabolites. We present a girl aged 11 years who manifested with a hypertensive crisis secondary to an adrenal tumour but with unexpectedly normal urinary metanephrine and catecholamine results. She improved spontaneously following the crisis and underwent surgery later. The histopathological study confirmed a pheochromocytoma with large central necrosis. Her genetic screening reported a pathogenic von Hippel-Lindau gene mutation. Surveillance scan postsurgery detected no other tumours. Following the catecholamine crisis, an acute infarct occurred, resulting in extensive tumour necrosis and subsequent rapid remission of symptoms and paradoxically normal biochemical markers. Although not unheard of in adults, we believe this is the first reported case of an extensive spontaneous necrosis resulting in a biochemically normal pheochromocytoma in a child.

Pediatric pheochromocytoma: current status of diagnostic imaging and treatment procedures

PURPOSE OF REVIEW

To provide an overview of relevant data available and updated recommendations for management of pediatric patients with pheochromocytoma (PCC).

RECENT FINDINGS

Much of the available data surrounding pediatric PCC is in the form of case reports and case series. With the accumulation of data over time, pediatric PCC does in fact differ significantly from not only what is known in the adult population, but also from classic teaching. Pediatric patients are much more likely to have a hereditary predisposition as well as aggressive and malignant disease. Much of the recent literature focuses on defining these genetic syndromes in order to provide recommendations for screening and genetic counseling. Other recent advances center around developing treatments for metastatic disease. Timely diagnosis with plasma metanephrines and cross-sectional imaging, and appropriate preoperative medical optimization followed by surgical resection remain the center of treatment.

SUMMARY

Although rare and adult principles are applied to pediatric PCC, genetic testing plays a pivotal role in management of children, adolescents and young adults with PCC.