PET/MR in children. Initial clinical experience in paediatric oncology using an integrated PET/MR scanner.

Use of PET/MR in children has not previously been reported, to the best of our knowledge. Children with systemic malignancies may benefit from the reduced radiation exposure offered by PET/MR. We report our initial experience with PET/MR hybrid imaging and our current established sequence protocol after 21 PET/MR studies in 15 children with multifocal malignant diseases. The effective dose of a PET/MR scan was only about 20% that of the equivalent PET/CT examination. Simultaneous acquisition of PET and MR data combines the advantages of the two previously separate modalities. Furthermore, the technique also enables whole-body diffusion-weighted imaging (DWI) and statements to be made about the biological cellularity and nuclear/cytoplasmic ratio of tumours. Combined PET/MR saves time and resources. One disadvantage of PET/MR is that in order to have an effect, a significantly longer examination time is needed than with PET/CT. In our initial experience, PET/MR has turned out to be an unexpectedly stable and reliable hybrid imaging modality, which generates a complementary diagnostic study of great additional value.

Primary intracranial soft tissue sarcoma in children and adolescents: a cooperative analysis of the European CWS and HIT study groups.

Purely intracranial soft tissue sarcomas (ISTS) are very rare among children. A retrospective database analysis of the Cooperative Weichteilsarkom Studiengruppe (CWS) and brain tumor (HIT) registries was conducted to describe treatment and long-term outcome of children and adolescents with ISTS. Nineteen patients from Germany, Austria and Switzerland were reported between 1988 and 2009. Median age at diagnosis was 9.7 years (range, 0.5-17.8). Central pathological review was performed in 17 patients. Eleven patients underwent a total and five a subtotal tumor resection. A biopsy was done in one patient. In two patients no data concerning extent of initial resection was available. Radiotherapy was performed in 15 patients (first-line, n = 11; following progression, n = 4). All but one patient received chemotherapy (first-line, n = 7, following progression, n = 5; first-line and following progression, n = 6). With a median follow-up of 5.8 years (range, 0.6-19.8) ten patients were alive in either first or second complete remission. Seven patients died due to relapse or progression and two were alive with progressive disease. Estimated progression-free and overall survival at 5 years were 47 % (±12 %) and 74 % (±10 %), respectively. About 50 % of patients with ISTS remain relapse-free after 5 years. Multimodality treatment including complete tumor resection and radio-/chemotherapy is required to achieve sustained tumor control in patients with ISTS. Early initiation of postoperative non-surgical treatment seems to be important to prevent recurrence. Due to the intracranial localization local therapy should follow the recommendations used in brain tumors rather than in soft tissue sarcomas, whereas chemotherapy should be guided by histological subtype.

Fulminant and fatal course of acute lymphoblastic leukemia due to lactic acidosis and suspected abdominal compartment syndrome.

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy and its prognosis has considerably improved over the past 2 decades due to new therapeutic approaches. In some cases, however, it can develop very rapidly and cause possibly fatal complications. We report on the case of an 11-year-old boy with ALL, who rapidly developed severe lactic acidosis and abdominal compartment syndrome. He died of multiorgan failure only 5 days after diagnosis of ALL had been established. Autopsy revealed systemic leukemic infiltrations. We suppose that the mass of tumor cells induced a cascade of metabolic and endocrine reactions, which not only triggered the rapid progression of the disease but were also accountable for the lack of response to treatment. The pathophysiology of abdominal compartment syndrome as a rare and in our case ultimately fatal complication of ALL is described.

Residual lymph node metastasis in stage 4 neuroblastoma--advantage of radio-guided surgery?

Log-term prognosis of children suffering from high-risk neuroblastomas is characterized by a shortened event-free survival, especially if metastases remain after chemotherapy. We report the case of a 3-year-old boy afflicted with a stage 4 neuroblastoma and persistent residual lymph node metastases despite the administration of a various number of treatment modalities. The insertion of a MIBG (metaiodobenzylguanidine) single-photon emission computed tomography (SPECT)-CT and radio-guided surgery implementing a hand held gamma probe finally allowed the exact localization and resection of the suspected lymphatic tissue. As a consequence, the child has been under event-free remission for 20 months. Because study-based knowledge is missing due to the small number of affected patients, individual case reports are helpful to improve future treatment strategies.

Voriconazole pharmacokinetics and safety in immunocompromised children compared to adult patients.

The aim of this study was to investigate the pharmacokinetics and safety of voriconazole after intravenous (i.v.) administration in immunocompromised children (2 to 11 years old) and adults (20 to 60 years old) who required treatment for the prevention or therapy of systemic fungal infections. Nine pediatric patients were treated with a dose of 7 mg/kg i.v. every 12 h for a period of 10 days. Three children and 12 adults received two loading doses of 6 mg/kg i.v. every 12 h, followed by a maintenance dose of 5 mg/kg (children) or 4 mg/kg (adults) twice a day during the entire study period. Trough voriconazole levels in blood over 10 days of therapy and regular voriconazole levels in blood for up to 12 h postdose on day 3 were examined. Wide intra- and interindividual variations in plasma voriconazole levels were noted in each dose group and were most pronounced in the children receiving the 7-mg/kg dose. Five (56%) of them frequently had trough voriconazole levels in plasma below 1 microg/ml or above 6 microg/ml. The recommended dose of 7 mg/kg i.v. in children provides exposure (area under the concentration-time curve) comparable to that observed in adults receiving 4 mg/kg i.v. The children had significantly higher C(max) values; other pharmacokinetic parameters were not significantly different from those of adults. Voriconazole exhibits nonlinear pharmacokinetics in the majority of children. Voriconazole therapy was safe and well tolerated in pediatric and adult patients. The European Medicines Agency-approved i.v. dose of 7 mg/kg can be recommended for children aged 2 to <12 years.

Assessment of histological response of paediatric bone sarcomas using FDG PET in comparison to morphological volume measurement and standardized MRI parameters.

PURPOSE: The objective of this study was to evaluate positron emission tomography (PET) using (18)F-fluoro-2-deoxy-D-glucose (FDG) in comparison to volumetry and standardized magnetic resonance imaging (MRI) parameters for the assessment of histological response in paediatric bone sarcoma patients. METHODS: FDG PET and local MRI were performed in 27 paediatric sarcoma patients [Ewing sarcoma family of tumours (EWS), n = 16; osteosarcoma (OS), n = 11] prior to and after neoadjuvant chemotherapy before local tumour resection. Several parameters for assessment of response of the primary tumour to therapy by FDG PET and MRI were evaluated and compared with histopathological regression of the resected tumour as defined by Salzer-Kuntschik. RESULTS: FDG PET significantly discriminated responders from non-responders using the standardized uptake value (SUV) reduction and the absolute post-therapeutic SUV (SUV2) in the entire patient population (SUV, p = 0.005; SUV2, p = 0.011) as well as in the subgroup of OS patients (SUV, p = 0.009; SUV2, p = 0.028), but not in the EWS subgroup. The volume reduction measured by MRI/CT did not significantly discriminate responders from non-responders either in the entire population (p = 0.170) or in both subgroups (EWS, p = 0.950; OS, p = 1.000). The other MRI parameters alone or in combination were unreliable and did not improve the results. Comparing diagnostic parameters of FDG PET and local MRI, metabolic imaging showed high superiority in the subgroup of OS patients, while similar results were observed in the population of EWS. CONCLUSION: FDG PET appears to be a useful tool for non-invasive response assessment in the group of OS patients and is superior to MRI. In EWS patients, however, neither FDG PET nor volumetry or standardized MRI criteria enabled a reliable response assessment to be made after neoadjuvant treatment.

Determination of saliva trough levels for monitoring voriconazole therapy in immunocompromised children and adults.

To evaluate the reliability and practical use of saliva for therapeutic drug monitoring of the antifungal agent voriconazole in immunocompromised patients, a paired-sample study was conducted. Plasma and saliva trough levels were measured in seven children and nine adults who required treatment for the prevention or therapy of systemic fungal infections. The pediatric patients received a voriconazole dosage of 7 mg/kg intravenously twice a day. Adults were treated with two loading doses of 6 mg/kg intravenously followed by a maintenance dose of 4 mg/kg intravenously twice a day. Based on 104 paired plasma/saliva specimens, we found a significant correlation between the voriconazole concentrations in blood and saliva (r > 0.95). The median saliva/plasma voriconazole concentration ratio was 0.34 in children and 0.40 in adults. Intra- and interpatient variability in the saliva/plasma ratios were 22% and 23% in children and 16% and 24% in adults, respectively. Thirty-three percent of plasma trough levels were below 1.0 microg/mL or above 6.0 microg/mL and occurred in six pediatric and four adult patients. Monitoring of salivary concentrations proved to be a realistic alternative in patients when blood drawing is difficult. Especially in therapeutic drug monitoring, an easier sample collection being noninvasive and painless is more acceptable to patients, particularly children.

Mixed hepatoblastoma and teratoma of the liver in a 3-year-old child: a unique combination and clinical challenge.

Primary liver tumors in children are rare with malignant hepatoblastoma being the most common neoplasm. In this report, we describe the diagnosis and clinical management of a large liver tumor in a 3-year-old child that displayed the features of both, conventional hepatoblastoma and malignant teratoma. Pathological assessment on a pre-operative bioptical specimen showed an immature teratoid tumor with no area of hepatoblastic differentiation present. Histological and immunohistological examination of the resected tumor specimen additionally showed tumor areas of very different differentiation pattern intermixed with each other, namely areas of hepatoblastoma-typical and neuroblastoma-like morphology as well as areas of rhadomyosarcomatous differentiation.After chemotherapy the tumor size increased and an extended right hemihepatectomy was performed. Post-operatively, the general condition of the child improved and adjuvant chemotherapy was started two weeks later. 36 months after initial diagnosis the patient is healthy, in good general condition, and without any sign of residual tumor disease.Overall, we describe the diagnosis and clinical management of a large liver tumor in a 3-year-old child that displayed the features of both, conventional hepatoblastoma and malignant teratoma and was designated as mixed hepatoblastoma and teratoma. Though mesenchymal tumor portions can occur within hepatoblastomas, most commonly osteoid or chondroid, our case is different as it presents a large spectrum of mesenchymal and epithelial differentiation pattern in most of the lesion.

Multiple malignant and benign lesions in the liver in a child with adrenocortical carcinoma.

We report 4-year-old girl who was diagnosed with adrenocortical carcinoma when she was 2 years old. At the time of diagnosis there were no metastases, but 6 months later multiple liver metastases appeared. Following intensive chemotherapy the metastases resolved completely. Multifocal lesions were detected in the liver by US 16 months later. Their morphology on US and MRI differed from the previous metastases. Histopathological examination confirmed focal nodular hyperplasia. We discuss the origin and the uncommon appearance of multifocal nodular hyperplasia in hormone-active tumours such as adrenocortical carcinoma in children.

Central lactic acidosis, hyperventilation, and respiratory alkalosis: leading clinical features in a 3-year-old boy with malignant meningeal melanoma.

Meningeal tumors are extremely rare in children and are diagnostically as well as therapeutically challenging. Among the least common types of malignancies in childhood is malignant melanoma, counting for less than 1% of pediatric tumors. Due to the rarity and the wide spectrum of appearance, initial clinical features may be misleading. A 3-year-old boy was referred to our hospital with symptoms of hyperventilation, dyspnoea, tachycardia, respiratory alkalosis, inarticulate speech, and fatigue. Measurement of pH in cerebrospinal fluid (CSF) yielded central lactic acidosis despite alkalosis in peripheral blood. Diagnostic imaging procedures as well as histology and immunohistochemistry revealed the diagnosis of a malignant meningeal melanoma. We hypothesize that central lactate production of the tumor nests might have induced central acidification, thus inducing hyperventilation by stimulation of central chemoreceptors. This case is a model example of the key role of central pH as an inducer/suppressor of ventilation in humans and illustrates the critical importance of central pH for regulating both ventilation and acid-base homeostasis. Thus, pH of CSF should be measured whenever a malignant brain tumor is suspected.

Does the expression of c-kit (CD117) in neuroendocrine tumors represent a target for therapy?

Neuroendocrine tumors are very heterogeneous, develop from a variety of tissues, and can be difficult to diagnose. Without the clinical manifestation of metastases, it is often difficult to characterize them as malignant. Even so-called completely (R0) resected tumors can spread clinically visible metastases within a few months after initial surgery. Treatment options for neuroendocrine tumors including pheochromocytoma are limited. Molecular targeted therapies using tyrosine kinase inhibitors might prove to be helpful in patients with these tumors. In an immunohistochemical study, we examined KIT in 26 pheochromocytomas, 8 of which were malignant (3 adrenal pheochromocytomas, 5 paragangliomas). KIT expression was found in one of these 8 malignant tumors. This 2.5-cm-large adrenal pheochromocytoma originated from a woman with neurofibromatosis type 1 and spread into spine, skull, and lung. KIT expression could be demonstrated in 5% of tumor cells. On the basis of KIT expression immunohistochemically, we treated patients with neuroendocrine (i.e., medullary thyroid cancer) and other tumors with imatinib 400 mg per day, but without efficacy after 2 months of therapy. Similar results were shown by other investigators. Therefore, monotherapy with imatinib may not be efficacious in patients with neuroendocrine tumors that express KIT. Tyrosine kinase inhibitors such as sorafenib that targets several receptors in addition to KIT may be more efficacious in treating patients with neuroendocrine tumors.

Ethanol-lock technique in the treatment of bloodstream infections in pediatric oncology patients with broviac catheter.

PURPOSE: To assess the ethanol-lock technique as a means of treating central venous line infections. Bloodstream infections in patients with tunneled central venous catheters can lead to removal of the lines. METHODS: Twenty-eight children and adolescents aged 2 to 18 years, with different types of cancer, had Broviac catheters and presented with positive blood culture and clinical signs of infection between January 2000 and December 2001. The ethanol-lock technique was performed 24 times in 18 patients in addition to empiric (initially) and specific (after antibiogram) intravenous antibiotic treatment. In another 15 cases, 13 children were treated with systemic antibiotics alone. RESULTS: Sixty-seven percent of the patients treated with ethanol locks had no infectious relapse of any kind within 4 weeks of treatment or during subsequent aplasia, compared with 47% treated with systemic antibiotics alone. In one boy the catheter infection could not be cleared with systemic antibiotics alone, but after one course of ethanol locks no more blood culture-positive infectious episodes were observed. No severe clinical side effects of ethanol flush were observed. Mild symptoms that occurred were tiredness, headaches, dizziness, nausea, and light-headedness. CONCLUSIONS: The ethanol-lock technique appears to be a safe, well tolerated, and effective way to treat central venous line infections, even in small children. A prospective randomized study should be designed to compare antibiotic-lock, ethanol-lock technique, and systemic antibiotics alone in the treatment of device-associated bloodstream infection.

Recurrent polytopic chromaffin paragangliomas in a 9-year-old boy resulting from a novel germline mutation in the von Hippel-Lindau gene.

Pheochromocytomas are frequently associated with inherited cancer syndromes such as von Hippel-Lindau disease (VHL). Retinal angioma and hemangioblastomas of the central nervous system are hallmarks of VHL, but its clinical variety is remarkably broad. Pheochromocytomas as the sole or first manifestation of VHL are rare but have been observed. In this case report, the authors describe an unusual case of initial collapse, seizures, and hypertensive crisis in a child who later was found to have multiple extraadrenal pheochromocytomas. Molecular diagnostics revealed a novel point mutation in the VHL gene (VHL nt. 406 T-->G). Only 7 months after the first lesions had been removed, a new paraganglioma developed in the contralateral periadrenal region. When encountering pheochromocytomas in children, the clinician should be aware that an associated tumor syndrome might be present, and appropriate molecular screening should be initiated. Molecular genetics aid in the clinical decision-making and clinical management of individual patients with pheochromocytoma.