The association of neuroblastoma with myoclonic encephalopathy of infants: the use of magnetic resonance as an imaging modality

False-positive metaiodobenzylguanidine scan for neuroblastoma in a child with opsoclonus-myoclonus syndrome treated with adrenocorticotropic hormone (acth)

We describe the case of a 2-year-old girl with opsoclonus-myoclonus syndrome treated with chronic adrenocorticotropic hormone (ACTH) in which a metaiodobenzylguanidine scan showed abnormal radiotracer uptake in the left adrenal gland region, interpreted as the site of an occult neuroblastoma. As this finding was not corroborated by previous or subsequent metaiodobenzylguanidine scans or by computed tomography (CT) or magnetic resonance imaging (MRI), we attribute the finding to being a false-positive result from adrenal hyperplasia owing to chronic use of ACTH and not to neuroblastoma. Metaiodobenzylguanidine scintigraphy is an extremely important nuclear medicine examination tool used for the evaluation and staging of pediatric neuroblastoma. We highlight the need for cautious interpretation of metaiodobenzylguanidine as a screening tool for neuroblastoma in patients treated with ACTH.

Adrenocortical carcinoma in children. Review and recent innovations

Adrenocortical carcinoma in childhood is a rare potentially fatal disease. Despite its often dramatic presentation, there typically has been a distressingly long delay between the onset of symptoms and the time of diagnosis. This delay undoubtedly has contributed to the historically poor prognosis in these children by permitting the disease to reach an advanced stage before treatment is started. It is imperative that the physician recognizes the endocrine manifestations of these tumors early and has a high index of suspicion. Although biochemical and histologic evaluations are helpful, they often cannot differentiate benign lesions from malignant neoplasms and should not unduly delay intervention. Aggressive complete surgical resection continues to be the mainstay of treatment and is the best prognosticator of overall survival. The role of adjuvant therapy and chemotherapy continues to evolve. Molecular studies have increased understanding of cancer biology and may provide possible novel therapeutic approaches in the future. It is hoped that increased familiarity with this unusual tumor will result in earlier detection, prompt intervention, and improved survival for children with adrenocortical carcinoma.

Paraneoplastic manifestations in children

Paraneoplastic manifestations are signs and symptoms observed in patients with cancer, distant from the tumour or its metastases and not caused by invasion, obstruction or bulk mass. In children with cancer, paraneoplastic manifestations are rare and distinct from those observed in adults. Knowledge about paraneoplastic manifestations can be of great clinical importance because they may be the presenting sign of a tumour or its recurrence and hence facilitate early diagnosis. In contrast, they sometimes mask the symptoms of a tumour and cause diagnostic delay. In this review, paraneoplastic manifestations in children are described, including hypercalcaemia, Cushing syndrome, precocious puberty, opsoclonus/myoclonus, acquired von Willebrand disease, watery diarrhoea syndrome, and hypertension. The mechanisms causing these manifestations are also discussed.

Magnetic resonance imaging of pelvic tumors in children

Pelvic tumors in children may be large, complex and of unknown origin. Preoperative radiological information regarding tumor localization and extent becomes essential in these cases for proper staging and surgical planning. Magnetic resonance imaging (MRI) offers the ability to enhance the surgical preparation of children who present with a pelvic mass. Advantages of MRI over computerized tomography include improved soft tissue characterization, signal enhancement of neuroendocrine tumors and multiplanar imaging. These features better define the origin, size and extent of tumors. In addition, no ionizing radiation is required. Several examples of pelvic tumors are presented. The new anatomical information provided by MRI altered surgical planning previously based on computerized tomography findings alone.