Pancreatic involvement in neuroblastoma with radiologic-pathologic correlation: a single-institution experience.

OBJECTIVE: Pancreatic involvement in neuroblastoma is extremely rare, with few cases reported in the literature. We present imaging findings of pancreatic involvement in neuroblastoma with clinical and pathologic correlation in the largest documented series to date. SUBJECTS AND METHODS: We prospectively reported pancreatic involvement evident on multimodality imaging in neuroblastoma patients presenting to our institution from 1997 to 2011. Lesions were classified according to location within the pancreas, and imaging features were correlated with cytogenetic and surgicopathologic findings. RESULTS: Neuroblastoma involving the pancreas was evident on imaging of seven of 1031 patients (mean age, 6.6 years). One patient had pancreatic involvement at presentation, and six developed pancreatic disease at relapse or disease progression. Pancreatic lesions were most frequently initially identified on concurrent CT and (123)I-metaiodobenzylguanidine scintigraphy, and additional lesions initially were found on MRI and ultrasound. Five of seven patients had focal lesions, one had diffuse pancreatic involvement, and one had pancreatic extension from contiguous disease. The distribution of lesions favored the pancreatic body and tail. All patients had International Neuroblastoma Staging System stage 3 or 4 disease, Children's Oncology Group intermediate- or high-risk disease, and unfavorable histology at initial diagnosis. For the five patients with surgical correlation, pancreatic surgical specimens revealed neuroblastoma in three cases and ganglioneuroblastoma in two cases. CONCLUSION: Although rare, pancreatic involvement in neuroblastoma occurs. Its variable imaging appearance should be considered when evaluating the retroperitoneum in patients with known or suspected neuroblastoma, particularly because increased patient survival holds the potential for uncommon patterns of recurrence.

Positron emission tomography for response assessment in desmoplastic small round cell tumor.

BACKGROUND: Desmoplastic small round cell tumors (DSRCT) typically have a large stromal component and often are extensively disseminated in the peritoneal cavity at diagnosis. These factors contribute to difficulty in quantifying response to chemotherapy using RECIST or WHO criteria. This study compares the overall disease response to chemotherapy by fluorodeoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) in patients with DSRCT. METHODS: We conducted a retrospective chart review of 7 patients with DSRCT who were imaged by FDG-PET and CT at diagnosis and after 3 cycles of chemotherapy. Response to chemotherapy was graded according to EORTC metabolic response guidelines and RECIST. RESULTS: All tumors demonstrated some decrease in SUVmax (51%±21%) and longest diameter (23%±8%) with chemotherapy. The best response achieved by FDG-PET was a partial response in 6 patients and by CT was a partial response in 1 patient. Measured response was concordant between the 2 modalities in 2 patients. CONCLUSIONS: In this small series response measurement by FDG-PET did not always correlate with response measurement by CT. A greater decrease in metabolic activity as compared with size was seen in all patients. Further studies are needed to define the role of FDG-PET in assessing early response of DSRCT to chemotherapy.

Variable MR imaging appearances of focal nodular hyperplasia in pediatric cancer patients.

BACKGROUND: Focal nodular hyperplasia (FNH) is rare in the general pediatric population but is increasingly found in treated pediatric cancer patients. FNH can be incidentally found on CT and MRI and can be misdiagnosed as liver metastasis in patients with an oncological history. OBJECTIVE: To describe the MR imaging findings of FNH in pediatric cancer patients. MATERIALS AND METHODS: Ten children who had been treated for a primary malignancy and who were diagnosed with FNH from 2003 to 2010 were identified from a search for FNH in our pathology and radiology databases. Patients were included if they were treated for a primary malignancy and had undergone MR imaging of the liver including T1-weighted, T2-weighted and dynamic contrast-enhanced T1-weighted sequences. RESULTS: FNH from all patients (n=10) demonstrated typical homogeneous arterial enhancement on MRI. The FNH was often multiple and small (7/10 patients), lacking a central scar, with variable imaging characteristics including signal hyperintensity on both T1- and T2-weighted images (4/10 patients), especially in the setting of hepatic hemosiderosis. CONCLUSION: FNH has a variable MR appearance in pediatric cancer patients and should be considered in the differential diagnosis of hypervascular liver lesions.

Skeletal imaging effects of pamidronate therapy in osteosarcoma patients.

BACKGROUND: After observing metaphyseal changes in pediatric and young adult patients with osteosarcoma who were treated with pamidronate, we initiated a retrospective study to identify bone findings on computed radiography of the chest and extremities, chest CT, extremity MRI, and radionuclide bone scans in this population. OBJECTIVE: To review the generalized skeletal imaging findings on computed radiography, CT, and MR examinations in patients with osteosarcoma (OS) receiving pamidronate. MATERIALS AND METHODS: A retrospective review of 40 patients with newly diagnosed OS (mean age, 16.5 years) receiving pamidronate with chemotherapy were identified at one institution. Computed radiography, CT, MR, and bone scans on 36 patients were reviewed for osseous changes. RESULTS: Dense metaphyseal bands at the growth plates in long bones, epiphyseal ossification centers, anterior rib ends, sternum and spine were observed. Osseous changes occurred on CT in 69% of patients, and on computed chest radiography in 53%. Bone-within-bone appearance in the spine and ossification centers was identified on computed radiography in 36%. CONCLUSION: OS patients treated with pamidronate can develop metaphyseal sclerotic bands as well as epiphyseal and vertebral endplate sclerosis progressing to a bone-within-bone appearance. Findings occur more frequently in younger patients with open epiphyses.

Imaging of pediatric lymphomas.

Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) represent 10% to 15% of all malignancies occurring in children younger than 20 years of age. Advances in cross-sectional imaging and the availability of positron emission tomography (PET) and PET-CT have had a major impact on imaging and management of pediatric patients. This article reviews the clinical features of lymphoma, focusing on the spectrum of imaging findings seen in diagnosis, staging, and follow-up of HL and NHL. Pediatric NHL has four major histologic subtypes: Burkitt lymphoma, diffuse large B-cell lymphoma, anaplastic large cell lymphoma, and lymphoblastic lymphoma. The most important subtype of HL is nodular sclerosis.

Pancreaticoduodenectomy for pediatric and adolescent pancreatic malignancy: A single-center retrospective analysis.

PURPOSE: While pancreaticoduodenectomy (PD) has been extensively studied in adults, there are few data pertaining specifically to pediatric patients. We retrospectively analyzed PD-associated morbidity and mortality in pediatric patients. METHODS: Our analytic cohort included all consecutive patients ≤18years of age treated at our institution from 1993 to 2015 who underwent PD. Patient data (demographics, disease characteristics, surgical and adjuvant treatment, length of hospital stay, and postoperative course) were extracted from the medical records. RESULTS: We identified 12 children with a median age of 9years (7 female, 5 male). Final diagnoses were pancreatoblastoma (n=3), solid pseudopapillary tumor (n=3), neuroblastoma (n=2), rhabdomyosarcoma (n=2), and neuroendocrine carcinoma (n=2). Four patients underwent PD for resection of recurrent disease. 75% (9/12 patients) received neoadjuvant therapy. The median operative time was approximately 7hours with a mean blood loss of 590cm3. The distal pancreas was invaginated into the posterior stomach (n=3) or into the jejunum (n=5) or was directly sewn to the jejunal mucosa (n=4). There were no operative deaths. There were 4 patients (34%) with grade II complications, 1 with a grade IIIb complication (chest tube), and 1 with a grade IV complication (reexploration). The most common long-term morbidity was pancreas exocrine supplementation (n=10; 83%). Five patients (42%) diagnosed with either solid pseudopapillary tumor or rhabdomyosarcoma are currently alive with a mean survival of 77.4months. CONCLUSION: Pancreaticoduodenectomy is a feasible management strategy for pediatric pancreatic malignancies and is associated with acceptable morbidity and overall survival. Long-term outcome is mostly dependent on histology of the tumor. LEVEL OF EVIDENCE: Level IV; retrospective study with no comparison group.

Image-defined risk factors for nephrectomy in patients undergoing neuroblastoma resection.

BACKGROUND: Although nephrectomy rates are higher in children with neuroblastoma who have image-defined risk factors and/or high-risk disease who undergo resection prior to chemotherapy, no published data outline the key radiographic and clinical characteristics associated with nephrectomy. METHODS: With IRB approval, imaging studies of children undergoing primary resection of intraabdominal neuroblastoma between 2000 and 2014 were retrospectively reviewed. Fisher's exact and Wilcoxon rank-sum tests were used to compare categorical and continuous variables, respectively, with p-values adjusted for multiple testing using the false discovery rate approach. RESULTS: Twenty-seven of 380 consecutive patients with CT imaging obtained prior to primary neuroblastoma resection underwent partial or total nephrectomy. On preoperative imaging, renal vessel narrowing and encasement and tumor invasion of the renal hilum, pelvis, and/or parenchyma were present significantly more frequently among patients undergoing nephrectomy. Delayed renal excretion of contrast, hydronephrosis, and tumors with MYCN amplification were also more prevalent in the nephrectomy group. CONCLUSION: Encasement and narrowing of renal vessels, delayed excretion, and tumor invasion into the kidney, particularly pelvis and capsule invasion, are significantly associated with partial or total nephrectomy at initial neuroblastoma resection. These observations provide valuable information for surgical planning as well as presurgical discussions with families prior to neuroblastoma resection.

Gastric Volvulus Following Left Pneumonectomy in an Adolescent Patient.

Gastric volvulus is a rare post-pneumonectomy complication. Although it has been described previously, published cases are limited to an older patient population. We report the youngest case of postpneumonectomy gastric volvulus to date, occurring in an 18-year-old male with a history of inflammatory myofibroblastic pseudotumor who underwent left intrapericardial pneumonectomy, and presented 13 years later with chronic intermittent mesenteroaxial gastric volvulus. While postpneumonectomy gastric volvulus is a rare occurrence, it should remain in the differential diagnosis in postoperative thoracic surgical patients presenting with chest pain.

Experience with retroperitoneal partial nephrectomy in bilateral Wilms tumor.

INTRODUCTION: Retroperitoneal partial nephrectomy has not been studied as a surgical approach for children with bilateral Wilms tumor. There are advantages to this technique, including isolation of urine leaks to the retroperitoneum, decreased risk of bowel injury, and decreased time to resuming a diet. Presently, all bilateral Wilms tumors are treated with neoadjuvant chemotherapy and attempted nephron-sparing surgery. In this study, we compare the outcomes of the retroperitoneal and transabdominal approaches in doing partial nephrectomy for bilateral Wilms tumor. METHODS: With the institutional review board approval, we reviewed records of 14 pediatric patients with metachronous or synchronous bilateral Wilms tumors who underwent surgery after chemotherapy between 1994 and 2014. Only operative procedures with the intent to cure were included (n=15) and of these, 5 procedures were retroperitoneal and 10 were transabdominal in approach. Individual kidneys operated upon (n=26) were analyzed using the preoperative radius exophytic/endophytic nearness anterior/posterior location nephrometry score to ensure that resected tumors were comparable between the two surgical groups. Charts were retrospectively analyzed for intraoperative parameters and postoperative course. Differences between parameters were evaluated using Mann-Whitney and chi-square tests. RESULTS: Resected tumors in both surgical treatment groups had comparable sizes, nephrometry scores, and rates of anaplasia. Operative time, blood loss, and transfusion requirement were similar between the two groups. The extent of lymph node sampling and rates of R0 resection were equivalent. One adverse intraoperative event, a bowel enterotomy, was seen in the transabdominal group. Patients after retroperitoneal partial nephrectomy required half the time to return to an oral diet as compared with those after a transabdominal surgery, approaching statistical significance (p=0.08). Rates of the postoperative urine leak were similar, though two in the transabdominal group required reoperation for drainage. There were four recurrences, all in the transabdominal group. CONCLUSION: Our experience demonstrates that the retroperitoneal approach is equivalent to the transabdominal technique with regards to intraoperative complications, lymph node dissection, and R0 resection. Advantages include less time to resumption of oral feeding, decreased risk of bowel injury, and isolation of urine leaks to the retroperitoneum. It should be considered a viable surgical option in the treatment of bilateral Wilms tumors.

FDG PET/CT detection of intussusception caused by lymphoma in a pediatric patient.

A previously healthy 9-year-old boy presented to an outside hospital with a history of abdominal pain and vomiting. An abdominal x-ray was unremarkable. A CT of the abdomen and pelvis performed to evaluate possible obstruction after weight loss and vomiting over a 3-week period demonstrated a large retroperitoneal mass. Laparoscopic biopsy showed diffuse large B-cell lymphoma. FDG PET/CT was performed for staging. An ileocolic intussusception was identified on the PET/CT. The intussusception was successfully managed with medical treatment. We present FDG PET/CT findings in intussusception with non-Hodgkin lymphoma as the lead point in a pediatric patient.

Resectability and operative morbidity after chemotherapy in neuroblastoma patients with encasement of major visceral arteries.

BACKGROUND/PURPOSE: Image-defined vessel encasement is a significant risk factor for surgical complications and incomplete resection for intermediate-risk tumors. We sought to examine the impact of vessel encasement on complications or resectability in intermediate-risk or high-risk patients after neoadjuvant chemotherapy. METHODS: We retrospectively reviewed 207 consecutive patients with circumferential encasement of the renal vessels, celiac axis, and/or superior mesenteric artery (SMA) who underwent resection between 1991 and 2009. Specifically, we evaluated resection rates, complications, and outcome. RESULTS: Median age at diagnosis was 3.0 years, and 79% of patients had stage 4 disease. Of known MYCN status, 23.4% had MYCN amplification. Vessel encasement included renal vessels, celiac axis, or SMA alone in 107, 7, and 4 patients, respectively. Both the renal vessels and celiac axis were encased in 5 patients, renal vessels and SMA in 7 patients, and celiac axis and SMA in 14 patients. Sixty-three patients had all 3 vessels encased. The gross total resection (GTR) rate was 94%. No operative or postoperative deaths occurred. The overall complication rate was 34.8% (n = 72). Overall 5-year survival (± SEM) was 67.4% (± 7.4%). CONCLUSION: Encasement of major visceral arteries in patients with neuroblastoma who have received chemotherapy does not preclude gross total resection.

Do characteristics of pulmonary nodules on computed tomography in children with known osteosarcoma help distinguish whether the nodules are malignant or benign?

PURPOSE: To determine if selected computed tomography (CT) characteristics of pulmonary nodules in pediatric patients with osteosarcoma can help distinguish the nodules as benign or malignant. METHODS: The institutional review board approved this HIPAA (Health Insurance Portability and Accountability Act-compliant, retrospective study of 30 pediatric osteosarcoma patients (median age 14 years, range 8-22) who underwent chest CT with resection of 117 pulmonary nodules from January 2001 to December 2006. Two pediatric radiologists and one chest radiologist independently and retrospectively reviewed the CT scans and classified nodules as benign, malignant, or indeterminate on the basis of nodule size, laterality, number, location, growth, density, margin appearance, and calcification. Generalized estimating equations were used to examine which characteristics were independent predictors of nodule malignancy. RESULTS: Of the 117 nodules, 80 (68%) were malignant and 37 (32%) were benign by pathologic review. The readers correctly classified 93% to 94% of the malignant nodules. For benign lesions, the results were not as accurate, with the readers correctly classifying only 11% to 30% of lesions. Most of the benign lesions were classified as indeterminate by the readers (54%-65%). Nodule size (≥5 mm) and the presence of calcifications were associated with an increased probability of malignancy (P b .05). CONCLUSION: On chest CT, nodule size 5 mm or greater and the presence of calcifications are associated with an increased probability of malignant nodule histology in pediatric patients with osteosarcoma. However, nodule characteristics, apart from size and calcification, at chest CT cannot reliably distinguish benign from malignant pulmonary nodules in these patients.

Addition of pamidronate to chemotherapy for the treatment of osteosarcoma.

BACKGROUND: This study evaluated the safety and feasibility of the addition of pamidronate to chemotherapy for treatment of osteosarcoma. METHODS: The authors treated 40 patients with osteosarcoma with cisplatin, doxorubicin, and methotrexate with the addition of pamidronate 2 mg/kg/dose (max dose 90 mg) monthly for 12 doses. Survival, event-free survival (EFS), and durability of orthopedic reconstruction were evaluated. RESULTS: For patients with localized disease, event-free survival (EFS) at 5 years was 72% and overall survival 93%. For patients with metastatic disease, EFS at 5 years was 45% and overall survival 64%. Toxicity was similar to patients treated with chemotherapy alone. Thirteen of 14 uncemented implants demonstrated successful osteointegration. Among allograft reconstructions, there were 2 graft failures, 4 delayed unions, and 6 successful grafts. Overall, 5 of 33 reconstructions failed. There were no stress fractures or growth disturbances. CONCLUSIONS: Pamidronate can be safely incorporated with chemotherapy for the treatment of osteosarcoma. It does not impair the efficacy of chemotherapy. Pamidronate may improve the durability of limb reconstruction.

Computed tomographic scan of the chest underestimates the number of metastatic lesions in osteosarcoma.

PURPOSE: Survival in osteosarcoma correlates with complete resection of primary and metastatic disease. The feasibility of complete pulmonary metastasectomy using thoracoscopy has been raised. Because palpation is not possible, minimally invasive techniques require preoperative radiological enumeration and localization of metastases not presenting at the lung surface. We hypothesized that computed tomographic (CT) scanning underestimated the number of pulmonary metastases in these patients. METHODS: Institutional review board approval was obtained. We determined the association between the number of lesions identified by CT scanning and the number of metastases found at thoracotomies for metastatic osteosarcoma from May 1996 to October 2004. Correlations between CT findings and pathology results were computed using the Kendall tau-b correlation coefficient. Depth, in millimeters, from the pleural surface was measured for those lesions seen on CT scan. RESULTS: We analyzed 54 consecutive thoracotomies performed in 28 patients for whom complete imaging was available. Computed tomographic scanning was performed a median of 20 days before thoracotomy (range, 1-85 days). Correlation between the number of lesions identified by CT and the number of metastases resected at surgery was poor, with a Kendall tau-b correlation coefficient of 0.45 (P < .001). In 19 (35%) of 54 thoracotomies, CT scanning underestimated the number of pathologically proven, viable and nonviable metastases found by the surgeon. Accounting for viable metastases only, correlation between the number of lesions identified by CT and the number of metastases resected at surgery was 0.50 (P < .001), and CT scanning underestimated the number of viable metastases present in 14 (26%) of 54 thoracotomies. Many lesions (32%) were pleural-based, but nearly half (47%) were 5 mm or deeper from the pleural surface of the lung. CONCLUSIONS: Even in the era of modern CT scanning, only a very rough correlation exists between CT findings and the number of lesions identified at thoracotomy. In more than one third of thoracotomies in our series, metastases would have been missed by any tactic besides manual palpation of the lung during open thoracotomy. Minimal access procedures should not be the approach of choice if the goal is resection of all pulmonary metastases in osteosarcoma.