[The VIP-secreting tumor as a differential diagnosis of protracted diarrhea in pediatrics]. / Der VIP-produzierende Tumor in der Pädiatrie als Differenzialdiagnose der protrahierten Diarrhö

BACKGROUND: Vasoactive intestinal peptide (VIP) can be produced by mature neurogenic tumors. Pathologically elevated VIP plasma levels cause secretory diarrhea with excessive loss of water and electrolytes. Despite the clinical severity diagnosis of a VIP-secreting tumor is often delayed and subsequently its extirpation as the mainstay of therapy. PATIENTS: We report on two patients with ganglioneuroblastoma and secretory diarrhea. We contrast the case of a 13-month-old boy with advanced symptoms of secretory diarrhea, high VIP plasma levels, and late diagnosis to the case of a 14-month-old boy with mild secretory diarrhea and normal VIP plasma levels but positive proof of VIP in tumor tissue. Reviewing the literature we found 57 cases of pediatric VIP-secreting tumors. RESULTS: The clinical situation is characterized by the typical symptoms of secretory diarrhea with hypokalemia and metabolic acidosis. Histopathology predominantly reveals ganglioneuroblastoma or ganglioneuroma. The symptoms mostly stop after complete resection of the tumor whereas lack of resection is associated with elevated mortality rates. CONCLUSIONS: In case of prolonged therapy-resistant secretory diarrhea the existence of a VIP-secreting tumor should be considered. Diagnostic work-up should include the assessment of VIP plasma levels, catecholamines in urine, and appropriate imaging techniques in order to rule out or confirm the possibility of a VIP producing tumor.

[Value of 123I-MIBG scanning, neuron-specific enolase and serum ferritin in the diagnosis and follow-up of patients with neuroblastoma]. / Valor del rastreo con 123I-MIBG, enolasa neuronal específica y ferritina sérica en el diagnóstico y seguimiento de pacientes con neuroblastoma.

INTRODUCTION: The neuroblastoma (NB) is one of the most common pediatric malignant neoplasms. The most commonly used tumor markers in the diagnosis and follow-up of this tumor are the serum neuron-specific enolase (NSE), ferritin and lactic dehydrogenase and urinary vanillymandelic and homovanillic acid. The common imaging modalities are CT, MRI and 123I or 131I-meta-iodobenzylguanidine scintigraphy. AIM: The aim of this study is to assess the value of 123I-meta-iodobenzylguanidine (MIBG) scintigraphy and serum determinations of NSE and ferritin in the diagnosis and evolution of NB patients. MATERIAL AND METHODS: 20 patients (8 female, 12 male) whose ages ranged from 2 months to 9 years with a mean age of 2.64 years diagnosed of NB. 47 123I-MIBG scans, 47 NSE determinations and 47 ferritin ones were selected. RESULTS: At the time of diagnosis, 100% of the 123I-MIBG scans were positive. 65% of NSE determinations presented clearly pathological levels and 15% were very near to the cut-off point. Only 45% of the ferritin levels were increased. The differences between the lesions visible by 123I-MIBG scanning before and 3 months after treatment as well as NSE and ferritin levels were studied. When the Student's T test was applied, we found statistically significant pre and post-treatment differences in 123I-MIBG scanning and NSE. In the case of ferritin, there was no statistical significance in spite of the decrease in the values. The direct correlation and Spearman correlation between laboratory data and 123I-MIBG scanning as well as correlation between NSE and ferritin were also studied. There was a good correlation between 123I-MIBG and NSE and between NSE and ferritin. We have also studied the data in 7 relapses. CONCLUSIONS: 123I-MIBG scintigraphy and serum determination of NSE are two successful diagnostic tools for the diagnosis and evolution of NB patients.