Diagnosis and Management of Nonislet Cell Tumor Hypoglycemia: Case Series and Review of the Literature

Peripheral primitive neuroectodermal tumor associated with paraneoplastic Cushing's syndrome: The rare case

Introduction

Primitive neuroectodermal tumors (PNET) form a group of tumors defined by their appearance that are thought to develop from primitive (undifferentiated) nerve cells in the brain. They are rare tumors and their incidence is not well defined.

Case presentation

An 18-month-old male presenting with typical Cushingoid appearance (moon face, central obesity, hirsutism and growth arrest) was admitted for evaluation of endocrine problems. Subsequent laboratory studies revealed markedly elevated adrenocorticotropic (ACTH) and cortisol levels, as well as a hypokalemic metabolic alkalosis, these data are consistent with the diagnosis of Cushing's disease. He was treated with metyrapone to control hypercortisolemia. One month and a half later, a mass was detected in the abdomen by ultrasonography. An abdominal Computed tomography confirmed a large heterogeneous retroperitoneal mass with a significant amount of extension into surrounding structures which was removed by laparoscopic abdominal surgery. The patient's symptoms completely resolved and the ACTH and cortisol levels were also greatly reduced. Histologically, the tumor tissue consistent with the diagnosis of the retroperitoneal primitive neuroectodermal tumor which was confirmed immunohistochemically. This case demonstrates the successful diagnosis and treatment of a rare neoplasm.

Conclusion

This is the first rare case with ectopic ACTH syndrome caused by the peripheral primitive neuroectodermal tumor.

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Paraneoplastic Cushing's syndrome has been attributed to ectopic ACTH secretion.

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Primitive neuroectodermal tumor secret ectopic ACTH and make Cushing's syndrome.

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Our case is an 18-month-old male presenting Cushing's syndrome because of retroperitoneal primitive neuroectodermal tumor.

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After remove of tumor,the patient's symptoms completely resolved.

Paraneoplastic endocrine syndromes

The majority of neoplasms are responsible for symptoms caused by mass effects to surrounding tissues and/or through the development of metastases. However, occasionally neoplasms, with or without endocrine differentiation, acquire the ability to secrete a variety of bioactive substances or induce immune cross-reactivity with the normal tissues that can lead to the development of characteristic clinical syndromes. These syndromes are named endocrine paraneoplastic syndromes when the specific secretory components (hormones, peptides or cytokines) are unrelated to the anticipated tissue or organ of origin. Endocrine paraneoplastic syndromes can complicate the patient's clinical course, response to treatment, impact prognosis and even be confused as metastatic spread. These syndromes can precede, occur concomitantly or present at a later stage of tumour development, and along with the secreted substances constitute the biological 'fingerprint' of the tumour. Their detection can facilitate early diagnosis of the underlying neoplasia, monitor response to treatment and/or detect early recurrences following successful initial management. Although when associated with tumours of low malignant potential they usually do not affect long-term outcome, in cases of highly malignant tumours, endocrine paraneoplastic syndromes are usually associated with poorer survival outcomes. Recent medical advances have not only improved our understanding of paraneoplastic syndrome pathogenesis in general but also enhanced their diagnosis and treatment. Yet, given the rarity of endocrine paraneoplastic syndromes, there is a paucity of prospective clinical trials to guide management. The development of well-designed prospective multicentre trials remains a priority in the field in order to fully characterise these syndromes and provide evidence-based diagnostic and therapeutic protocols.

Paraneoplastic syndromes: an approach to diagnosis and treatment

Recent medical advances have improved the understanding, diagnosis, and treatment of paraneoplastic syndromes. These disorders arise from tumor secretion of hormones, peptides, or cytokines or from immune cross-reactivity between malignant and normal tissues. Paraneoplastic syndromes may affect diverse organ systems, most notably the endocrine, neurologic, dermatologic, rheumatologic, and hematologic systems. The most commonly associated malignancies include small cell lung cancer, breast cancer, gynecologic tumors, and hematologic malignancies. In some instances, the timely diagnosis of these conditions may lead to detection of an otherwise clinically occult tumor at an early and highly treatable stage. Because paraneoplastic syndromes often cause considerable morbidity, effective treatment can improve patient quality of life, enhance the delivery of cancer therapy, and prolong survival. Treatments include addressing the underlying malignancy, immunosuppression (for neurologic, dermatologic, and rheumatologic paraneoplastic syndromes), and correction of electrolyte and hormonal derangements (for endocrine paraneoplastic syndromes). This review focuses on the diagnosis and treatment of paraneoplastic syndromes, with emphasis on those most frequently encountered clinically. Initial literature searches for this review were conducted using PubMed and the keyword paraneoplastic in conjunction with keywords such as malignancy, SIADH, and limbic encephalitis, depending on the particular topic. Date limitations typically were not used, but preference was given to recent articles when possible.

Electrolyte complications of malignancy

A thorough working knowledge of the diagnosis and treatment of life-threatening electrolyte abnormalities in cancer patients, especially hyponatremia, hypoglycemia, and hypercalcemia, is essential to the successful practice of emergency medicine. Although most minor abnormalities have no specific treatment, severe clinical manifestations of several notable electrolytes occur with significant frequency in the setting of malignancy. The treatment of life-threatening electrolyte abnormalities is reviewed here. Promising future treatments directed at the underlying physiology are also introduced.