Peritoneal Malignancy in Children: A Pictorial Review.

Peritoneal malignancies are a rare occurrence in children, often metastatic and rarely originating primarily in the peritoneum. The imaging findings of these entities in the pediatric age have not been recently reviewed or they have been previously described or depicted mostly as part of articles discussing each entity separately. This is a review of the most relevant peritoneal malignancies in childhood emphasizing imaging features. Knowledge of these appearances may facilitate diagnosis and staging of these neoplasms.

Nestin is not essential for development of the CNS but required for dispersion of acetylcholine receptor clusters at the area of neuromuscular junctions.

Nestin is expressed in many different progenitors during development including those of the CNS, heart, skeletal muscle, and kidney. The adult expression is mainly restricted to the subependymal zone and dentate gyrus of the brain, the neuromuscular junction, and renal podocytes. In addition, this intermediate filament protein has served as a marker of neural stem/progenitor cells for close to 20 years. Therefore it is surprising that its function in development and adult physiology is still poorly understood. Here we report that nestin deficiency is compatible with normal development of the CNS. The mutant mice, however, show impaired motor coordination. Furthermore, we found that the number of acetylcholine receptor clusters, the nerve length, and the endplate bandwidth are significantly increased in neuromuscular junction area of nestin-deficient mice. This is similar to the phenotype described for deficiency of cyclin-dependent kinase 5 (Cdk5), a candidate downstream affecter of nestin. Moreover, we demonstrate that nestin deficiency can rescue maintenance of acetylcholine receptor clusters in the absence of agrin, similar to Cdk5/agrin double knock-outs, suggesting that the observed nestin deficiency phenotype is the consequence of aberrant Cdk5 activity.

Risk factors, complications, and outcomes of gallstones in children: a single-center review.

BACKGROUND AND OBJECTIVE: The increasing use of sonography has resulted in an increase in the proportion of children with gallstones who are asymptomatic at the time of diagnosis. In adults, the literature supports expectant management of clinically silent gallstones. The evidence for this management approach in children is limited to a number of small series. Our objective was to review the risk factors, complications, and outcomes of gallstones at our institution, particularly in those patients who are asymptomatic at the time of initial diagnosis. MATERIALS AND METHODS: We reviewed 382 cases of gallstones in children. These patients were diagnosed with sonography. Data on age at diagnosis, presentation, sonographic findings, risk factors, complications, surgery, and follow-up were collected. A chi2 test was used to compare the complication rates between symptomatic and asymptomatic groups. Descriptive statistics were used to analyze the sample. RESULTS: At diagnosis, 50.5% of children were asymptomatic; these patients were diagnosed at a mean age of 8.23 years. Compared with symptomatic patients, they were less likely to have a hemolytic anemia but more likely to have other risk factors, including cardiac surgery, leukemia and lymphoma, short bowel syndrome, or exposure to total parenteral nutrition or cephalosporins. These patients had a lower rate of complications than the symptomatic patients (4.6% vs 28.2% of symptomatic, P < 0.0001) and only 3.1% developed symptoms that necessitated surgery (vs 59.0% of symptomatic). Of the 58 (15.1%) diagnosed in infancy, 47 (81.0%) were asymptomatic. The infant group also had low rates of complications (8.6%) and cholecystectomy (1.7%). In cases with sonographic follow-up, resolution of gallstones was demonstrated in 16.5% of asymptomatic patients and in 34.1% of infants. CONCLUSIONS: The data suggest that clinically silent gallstones in children and infants are associated with low rates of complications and can be managed conservatively, unless complications occur. Patients with sickle cell disease, spherocytosis, and elliptocytosis had high complication rates and required surgery more often.

Low-level TOP2A amplification in prostate cancer is associated with HER2 duplication, androgen resistance, and decreased survival.

HER2 and TOP2A genes, located on 17q, can be coamplified in cancer. Overexpression of both genes has been reported in high-grade, androgen-resistant prostate cancer. Both genes have not been compared in a single prostate cancer study and the frequency of TOP2A amplifications in prostate cancer is unknown. Using tissue microarrays, we did immunohistochemistry and fluorescence in situ hybridization for HER2 and TOP2A in 100 prostate cancers (41 localized and 59 advanced) and 42 cases of benign prostatic hyperplasia (BPH). Amplification was defined as a target/centromere signal ratio of > or =1.5. HER2 immunohistochemistry was scored from 0 to 3+. Percentage nuclei staining for topoisomerase IIalpha (topoIIalpha) was recorded; overexpression was defined as > or =5% cells staining. Eighteen (31%) advanced prostate cancers showed topoIIalpha overexpression; 12 (26%) showed TOP2A low-level amplification; 9 (16%) expressed HER2; and 6 (13%) showed HER2 low-level amplification. No high-level amplification of either gene (target/centromere signal ratio of > or =3.0) was detected. TOP2A coexpression and coamplification were seen in 75% and 66% of HER2-positive cases, respectively. Localized prostate cancer or BPH showed no gene amplification or topoIIalpha overexpression. Gene amplification or overexpression correlated with high stage and Gleason score. The presence of TOP2A amplification in advanced cancer was associated with androgen resistance and decreased survival by multivariate analysis. This is the first study to document low-level TOP2A amplification in prostate cancer and an association with reduced survival. TOP2A amplification may occur with or without HER2 duplication and is often associated with topoIIalpha expression. Therapies directed against topoIIalpha (and HER2) in such patients may improve survival.

A comparison study between the saturation-recovery-T1 and CASL MRI methods for quantitative CBF imaging.

The saturation-recovery (SR)-T1 MRI method for quantitatively imaging cerebral blood flow (CBF) change (ΔCBF) concurrently with the blood oxygenation level dependence (BOLD) alteration has been recently developed and validated by simultaneous measurement of relative CBF change using laser Doppler flowmetry (LDF) in rats at 9.4T. In this study, ΔCBF induced by mildly transient hypercapnia and measured by the SR-T1 MRI method was rigorously compared with an established perfusion MRI method-continuous arterial spin labeling (CASL) approach in normal and preclinical middle cerebral artery occlusion (MCAo) rat models. The results show an excellent agreement between ΔCBF values measured with these two imaging methods. Moreover, the intrinsic longitudinal relaxation rate (R1int) was experimentally determined in vivo in normal rat brains at 9.4T by comparing two independent measures of the apparent longitudinal relaxation rate (R1app) and CBF measured by the CSAL approach across a wide range of perfusion. In turn, the R1int constant can be employed to calculate the CBF value based on the R1app measurement in healthy brain. This comparison study validates the fundamental relationship for linking brain tissue water R1app and cerebral perfusion, demonstrates the feasibility of imaging and quantifying both CBF and its change using the SR-T1 MRI method in vivo.

Focal middle cerebral artery ischemia in rats via a transfemoral approach using a custom designed microwire.

OBJECTIVES: The aim of this study was to develop a reliable and repeatable method of inducing focal middle cerebral artery occlusion (MCAo) in rats without ligation of the external carotid artery (ECA), while reducing the risk of subarachnoid hemorrhage. METHODS: We prototyped microwires with different diameters (0.0120 inch, 0.0115 inch, 0.0110 inch), materials, and construction methods (coil-on-core, extruded polymer jacket-on-core). Under fluoroscopic guidance and using femoral artery access, the microwires were navigated into the internal carotid artery of male Wistar rats (n=50, weight 376±64 g) to induce MCAo for 1 or 2 h. We performed neurological assessments at baseline, and at 3, 24, 72, and 168 h after MCAo. MRI measurements were performed on a 9.4 T scanner at 1 and 7 days post-injury. RESULTS: The 0.0115 inch microwire with polymer jacket-on-core provided the most successful outcome. At 1 and 7 days post-injury, we observed similar infarction volumes for 1 and 2 h MCAo in the MRI study. Infarcted lesion volumes in both MCAo groups were significantly reduced at 7 days compared with 1 day post-injury. The trend in longitudinal changes for the scores of different neurological assessments was confirmed to be significant after the injury, but both groups showed a similar trend of neurological deficits over the course of the study. CONCLUSIONS: We have developed a reliable and repeatable MCAo method in rats, allowing for precise occlusion of the MCA under direct fluoroscopic visualization without alteration of the cerebral hemodynamics associated with ECA ligation. The custom designed microwire can also be sized for targeted focal ischemia in larger animals.

Anaplastic large cell lymphoma: a unique presentation with urinary bladder involvement: a case report.

Anaplastic large cell lymphoma (ALCL) is a T-cell lymphoma composed of large pleomorphic CD30-positive cells. While systemic ALCL frequently involves extranodal sites, involvement of the urinary bladder is extremely rare. We report a case of systemic ALCL presenting with bladder involvement. A 28-year-old man presented with hematuria, dysuria, and lower abdominal pain. Imaging revealed pelvic lymphadenopathy and a thickened bladder wall. Bladder biopsies showed diffuse infiltration of the lamina propria by large pleomorphic cells, with preservation of the overlying urothelium. Immunohistochemistry demonstrated cell membrane and Golgi region staining for CD30 and epithelial membrane antigen. This is the first documented instance of systemic ALCL presenting with bladder symptoms.

A Novel Preclinical Model of Moderate Primary Blast-Induced Traumatic Brain Injury.

Blast-induced traumatic brain injury (bTBI) is the "signature" injury of the recent Iraq and Afghanistan wars. Here, we present a novel method to induce bTBI using shock wave (SW) lithotripsy. Using a lithotripsy machine, Wistar rats (N = 70; 408.3 ± 93 g) received five SW pulses to the right side of the frontal cortex at 24 kV and a frequency of 60 Hz. Animals were then randomly divided into three study endpoints: 24 h (n = 25), 72 h (n = 19) and 168 h (n = 26). Neurological and behavioral assessments (Garcia's test, beam walking, Rotarod, and elevated plus maze) were performed at the baseline, and further assessments followed at 3, 6, 24, 72, and 168 h post-injury, if applicable. We performed digital subtraction angiography (DSA) to assess presence of cerebral vasospasm due to induced bTBI. Damage to brain tissue was assessed by an overall histological severity (OHS) score based on depth of injury, area of hemorrhage, and extent of axonal injury. Except for beam walking, OHS was significantly correlated with the other three outcome measures with at least one of their assessments during the first 6 h after the experiment. OHS manifested the highest absolute correlation coefficients with anxiety at the baseline and 6 h post-injury (r(baseline) = -0.75, r(6hrs) = 0.85; p<0.05). Median hemispheric differences for contrast peak values (obtained from DSA studies) for 24, 72, and 168 h endpoints were 3.45%, 3.05% and 0.2%, respectively, with statistically significant differences at 1 versus 7 d (p<0.05) and 3 versus 7 d (p<0.01). In this study, we successfully established a preclinical rat model of bTBI with characteristics similar to those observed in clinical cases. This new method may be useful for future investigations aimed at understanding bTBI pathophysiology.

Clinical and neuropathological features of X-linked spinal muscular atrophy (SMAX2) associated with a novel mutation in the UBA1 gene.

Infantile-onset X-linked spinal muscular atrophy (SMAX2) is a rare lethal disorder linked to mutations in the UBA1 (previously UBE1) gene, encoding ubiquitin-activating enzyme 1 that has an important role in the ubiquitin-proteasome pathway. Published pathological reports are scarce. Here we report a male infant who presented from birth with predominantly truncal hypotonia following an antenatal history of reduced fetal movements. He had a myopathic face, profound weakness, multiple contractures and areflexia. Creatine kinase was moderately raised. Brain MRI showed non-specific symmetrical periventricular white matter changes. Neurophysiology revealed evidence of motor and sensory involvement and muscle biopsy showed marked inflammatory changes with subtle features suggestive of acute denervation. UBA1 sequencing revealed a novel hemizygous missense mutation (c.1670A>T; p.Glu557Val). He died from progressive respiratory failure at 4 months. On post mortem assessment, in addition to severe ventral motor neuron pathology, there was widespread involvement of the sensory system, as well as developmental and degenerative cerebellar abnormalities. In contrast to typical SMN1-associated SMA, the thalamus was unaffected. These findings indicate that SMAX2 is more accurately classified as a motor sensory neuronopathy rather than a pure anterior horn cell disorder. Ubiquitin-proteasome pathway defects may not only cause neurodegeneration but also affect normal neuronal development.

Diagnostic utility of nestin expression in pediatric tumors in the region of the kidney.

Nestin is an intermediate filament that was first identified in neuroepithelial stem cells. During embryogenesis, nestin is expressed in a number of cell types, including neural crest cells and developing myocytes. We have recently shown that nestin is expressed in human podocytes and nephrogenic blastema. We sought to determine the utility of nestin expression in distinguishing pediatric tumors in the region of the kidney. Cases studied included Wilms tumor (n=24), nephroblastomatosis (n=6), renal cell carcinoma (n=19), renal clear cell sarcoma (n=9), mesoblastic nephroma (n=9), neuroblastoma (n=11), malignant rhabdoid tumor (n=8 including 2 renal), Ewing sarcoma (n=16 including 1 renal, 7 soft tissue, and 8 bone), intra-abdominal desmoplastic small round cell tumor (n=5), and rhabdomyosarcoma (n=8, all extrarenal). Nestin expression was assessed semiquantitatively by immunohistochemistry and then scored as positive or negative. All cases of Wilms tumor, mesoblastic nephroma, rhabdomyosarcoma, neuroblastoma, malignant rhabdoid tumor, and desmoplastic small round cell tumor were nestin-positive. In Wilms tumor and nephroblastomatosis, nestin was expressed in blastema and glomeruloid structures, but not tubules. In neuroblastoma, positive staining was detected regardless of degree of differentiation. The majority of Ewing sarcoma and renal cell carcinoma were negative. Expression in clear cell sarcoma was variable with 5 cases negative and 4 cases positive. Thus, nestin is a highly sensitive, but nonspecific, marker of Wilms tumor in the context of tumors that may occur in or around the kidney. Nestin reactivity may be useful in differentiating Wilms tumor from Ewing sarcoma, renal cell carcinoma, or nestin-negative clear cell sarcoma.

A new molecular variant of desmoplastic small round cell tumor: significance of WT1 immunostaining in this entity.

Desmoplastic small round cell tumor is a rare aggressive neoplasm, often presenting in young adult males. Although the classic features are well described, considerable clinical, pathologic, and immunohistochemical variation has been reported. The defining feature is a reciprocal translocation, t(11;22)(p13;q12), which fuses EWS on chromosome 22 to WT1 on chromosome 11. WT1 immunohistochemistry is reportedly useful in distinguishing desmoplastic small round cell tumor from other tumors. Herein, we describe a desmoplastic small round cell tumor of soft tissue with an unusual pattern of WT1 expression associated with a novel variant EWS-WT1 fusion transcript. We compare WT1 expression pattern with 5 intra-abdominal desmoplastic small round cell tumors and review the literature on WT1 expression and variant transcripts in desmoplastic small round cell tumor. Immunohistochemistry for the N- and C-terminals of WT1 was performed in 6 desmoplastic small round cell tumors. The EWS-WT1 fusion transcript was confirmed in all cases by reverse transcriptase polymerase chain reaction. Sequencing of fusion transcripts and reverse transcriptase polymerase chain reaction for wild-type WT1 was performed in 4 cases. The soft tissue desmoplastic small round cell tumor was negative for the WT1 C-terminal and showed nuclear staining with the N-terminal antibody. This case demonstrated 2 novel fusion transcripts, both lacking WT1 exons 9 and 10 and one containing additional exons of WT1 (exons 3-7). This tumor also strongly expressed full-length WT1. Five intra-abdominal desmoplastic small round cell tumors showed nuclear staining for WT1 C-terminal, but not for the N-terminal antibody. Although WT1 immunohistochemistry reflects the EWS-WT1 fusion transcript in most desmoplastic small round cell tumors, some cases express full-length WT1 or have variant transcripts, resulting in atypical staining patterns. Hence, interpretation of WT1 immunostaining requires knowledge of antibody target epitopes and correlation with clinical, morphological, and molecular genetic findings for establishing a diagnosis of desmoplastic small round cell tumor.