SAGE Publications

Clinically responsive placental examination seeks to provide useful information regarding the etiology, prognosis, and recurrence risk of pregnancy disorders. The purpose of this study was to assemble and validate a complete set of the placental reaction patterns seen with amniotic fluid infection in the hope that this might provide a standardized diagnostic framework useful for practicing pathologists. Study cases (14 with amniotic fluid infection, 6 controls) were reviewed blindly by six pathologists after agreement on a standard set of diagnostic criteria. After analysis of initial results, criteria were refined and a second, overlapping set of cases were reviewed. Majority vote served as the gold standard. Grading and staging of maternal and fetal inflammatory responses was found to be more reproducible using a two- versus three-tiered grading system than a three-versus five-tiered staging system (overall agreement 81% vs. 71%). Sensitivity, specificity, and efficiency for individual observations ranged from 67–100% (24/30 > 90%). Reproducibility was measured by unweighted kappa values and interpreted as follows: < 0.2, poor; 0.2–0.6, fair/moderate; > 0.6, substantial. Kappa values for the 12 lesions evaluated in 20 cases by the six pathologists were: acute chorioamnionitis/maternal inflammatory response (any, 0.93; severe 0.76; advanced stage, 0.49); chronic (subacute) chorioamnionitis (0.25); acute chorioamnionitis/fetal inflammatory response (any, 0.90; severe, 0.55; advanced stage, 0.52); chorionic vessel thrombi (0.37); peripheral funisitis (0.84); acute villitis (0.90); acute intervillositis/intervillous abscesses (0.65), and decidual plasma cells (0.30). Adoption of this clearly defined, clinically relevant, and pathologically reproducible terminology could enhance clinicopathologic correlation and provide a framework for future clinical research.

Necrotizing enterocolitis (NEC), a disease affecting predominantly premature infants, is a leading cause of morbidity and mortality in neonatal intensive care units. Although several predisposing factors have been identified, such as prematurity, enteral feeding, and infection, its pathogenesis remains elusive. In the past 20 years, we have established several animal models of NEC in rats and found several endogenous mediators, especially platelet-activating factor (PAF), which may play a pivotal role in NEC. Injection of PAF induces intestinal necrosis, and PAF antagonists prevent the bowel injury induced by bacterial endotoxin, hypoxia, or challenge with tumor necrosis factor-α (TNF) plus endotoxin in adult rats. The same is true for lesions induced by hypoxia and enteral feeding in neonatal animals. Human patients with NEC show high levels of PAF and decreased plasma PAF-acetylhydrolase, the enzyme degrading PAF. The initial event in our experimental models of NEC is probably polymorphonuclear leukocyte (PMN) activation and adhesion to venules in the intestine, which initiates a local inflammatory reaction involving proinflammatory mediators including TNF, complement, prostaglandins, and leukotriene C₄. Subsequent norepinephrine release and mesenteric vasoconstriction result in splanchnic ischemia and reperfusion. Bacterial products (e.g., endotoxin) enter the intestinal tissue during local mucosal barrier breakdown, and endotoxin synergizes with PAF to amplify the inflammation. Reactive oxygen species produced by the activated leukocytes and by intestinal epithelial xanthine oxidase may be the final pathway for tissue injury. Protective mechanisms include nitric oxide produced by the constitutive (mainly neuronal) nitric oxide synthase, and indigenous probiotics such as Bifidobacteria infantis. The former maintains intestinal perfusion and the integrity of the mucosal barrier, and the latter keep virulent bacteria in check. The development of tissue injury depends on the balance between injurious and protective mechanisms.

The purpose of the study was to determine the epidemiological relationships in three unrelated cases of neonatal late-onset Group B streptococcal (GBS) disease and maternal breast-milk infection with GBS. All deliveries were by cesarean section; case 1 was at term, and cases 2 and 3 were at 32- and 33-wk gestation, respectively. Case 1 relates to a mother with clinical mastitis and recurrent GBS infection in a 20-day-old male infant. Following antibiotic therapy and cessation of breastfeeding, the infant recovered without sequelae. Case 2 refers to a mother with clinical mastitis and the occurrence of late-onset GBS disease in 5-wk-old male twins. Despite intervention, one infant died and the second became ill. Following antibiotic therapy and cessation of breast-feeding, the surviving infant recovered without sequelae. Case 3 refers to a mother with sub-clinical mastitis and late-onset GBS infection occurring in a 6-day-old female twin. Following intervention, the infant recovered but suffered a bilateral thalamic infarction resulting in developmental delay and a severe seizure disorder. Following recovery of GBS from an inapparent mastitis and cessation of breast-feeding, the second infant remained well. Blood cultures from all affected infants and maternal breast milk were positive for GBS. Epidemiological relationships between neonatal- and maternal-derived GBS isolates were confirmed by a random amplified polymorphic DNA polymerase chain reaction assay (RAPD-PCR). This study is significant in that it has demonstrated that maternal milk (in cases of either clinical or sub-clinical mastitis) can be a potential source of infection resulting in either late-onset or recurrent neonatal GBS disease.

The National Wilms Tumor Study (NWTS)-5, begun in August 1995, incorporates some important new definitions and concepts that have critical importance in determining therapy and prognosis. The criteria for stage 1 were refined to accommodate an important subset of stage 1 Wilms tumors that are being managed by nephrectomy alone, without the use of adjuvant therapy. The distinction between stages 1 and 2 in the renal sinus is no longer defined by the hilar plane but by the presence or absence of venous or lymphatic invasion. Specific problems encountered in the interpretation of the renal sinus are discussed here. The topographical definition of focal anaplasia has proven to be of prognostic value and is incorporated into the NWTS-5 study design.

Three of 70 small bowel transplant recipients were diagnosed with adenovirus enteritis. The biopsies were performed for surveillance in one patient at 2.7 years after transplantation and in two symptomatic children 1.5 years and 4.5 months after transplantation. In all three patients the characteristic epithelial changes were not noted by the primary observers. Two biopsies had been called “suggestive of acute rejection” and both patients had been so treated. One biopsy had been diagnosed as “regenerative”. Once the epithelial changes were recognized as being viral, confirmation was possible by stool culture in one patient, immunohistochemistry in two patients, or by lift technique of the H&E sections for electron microscopy. The immune suppression was reduced and none of the patients developed disseminated infection. As in other transplanted organs, such as lung and liver, adenovirus infection may be limited largely to the allograft but can be destructive. Early recognition of the characteristic changes that are illustrated can lead to confirmation of the virus and appropriate reduction of immune suppression. A mistaken diagnosis of rejection and augmentation of immune suppression can lead to viral dissemination and potential fatality.

Renal cell carcinomas (RCCs) are rare in children and studies of their subtypes and clinicopathologic associations are limited to small series. We identified 8 patients with RCC treated at our institution between 1981 and 2003, reviewed their clinicopathologic features, cytogenetics findings, and evaluated the status of TFE3 expression by immunohistochemistry and numerical chromosomal alterations by interphase fluorescent in situ hybridization on paraffin-embedded tissue. These 8 patients (5 female and 3 male) had diploidy, and 5 had morphologic features compatible with the recently described RCC associated with Xp11.2 translocations/TFE3 gene fusions and demonstrated nuclear labeling for TFE3 protein by immunohistochemistry. The translocation was confirmed in 2 of these 5 patients by conventional cytogenetics. One case was a high-grade nonpapillary RCC and the other was compatible with type 2 papillary RCC. Four patients showed at least 1 chromosomal gain including trisomy 7 and/or trisomy 17. None of the tumors from male patients showed evidence of loss of the Y chromosome, but 2 patients showed numerical abnormalities of X chromosome +add(X). Two patients had sickle cell disease, and 1 of these also had stage IV-S neuroblastoma. This study suggests that many cases of RCC in children reported under the terms “papillary” and “clear cell” likely represent Xp11.2 translocation/TFE3 gene fusion-associated RCC. It also emphasizes the unusual associations of RCC with neuroblastoma and sickle cell hemoglobinopathy, which need further study.

Two patients with hemophagocytic lymphohistiocytosis who presented with acute liver failure are reported. Both presented with fever, hepatosplenomegaly, markedly elevated liver function tests, abnormal coagulation profiles, and an increase in serum ferritin. Both infants were diagnosed with neonatal hemochromatosis based on a clinical picture of hepatic insufficiency with hyperferritinemia and were referred for liver transplantation. The first patient died of liver failure and septicemia before transplantation. Review of autopsy material revealed a hepatitis-like pattern and extensive infiltration of liver and other organs including bone marrow by histiocytes, some of which were hemophagocytic. The second patient underwent liver transplantation but died 44 days thereafter from progressive hemophagocytic lymphohistiocytosis. Examination of the resected liver demonstrated a hepatitis-like pattern, proliferation of histiocytes, and hemophagocytosis, and the bone marrow revealed hemophagocytic histiocytosis. Hemophagocytosis recurred in the allograft. Hepatic manifestations are common in hemophagocytic lymphohistiocytosis and overt hepatic failure may occur, but initial presentation as fulminant hepatic failure is not well recognized. Elevated serum ferritin can make the distinction from neonatal hemochromatosis and other forms of neonatal liver failure difficult. Hemophagocytic lymphohistiocytosis should be considered in the differential diagnosis of neonatal liver disease, especially when it is accompanied by cytopenias.

Histiocytoid cardiomyopathy (HC), a rare arrhythmogenic disorder, presents as difficult-to-control arrhythmias or sudden death in infants and children, particularly girls. Three cases are described with autopsy findings. In two cases, yellow-tan nodules were grossly visible in the myocardium; in the third case, no gross lesions were identified. Microscopic examination in all three cases revealed multiple, scattered clusters of histiocytoid myocytes which on ultrastructural examination were filled with abnormal mitochondria, scattered lipid droplets, and scanty myofibrils. These pathologic findings are similar to those previously described. The pathogenesis of this entity remains controversial. It was recently proposed that this disorder is X-linked dominant with the associated gene located in the region of Xp22.

Inflammatory myofibroblastic tumors (IMTs) are challenging lesions with respect to classification, differential diagnosis, and biologic potential. In children, extrapulmonary IMTs, particularly those from the abdomen or mesentery, are generally aggressive, with frequent local recurrences. There are few documented patients with distant metastasis, and most of these had metastases at presentation or developed metastases within months to a few years. We add to the short list of metastatic extrapulmonary IMTs a pediatric patient in whom the primary lesion was widespread in the abdomen at presentation and metastatic disease to the lung was diagnosed 9 years after the primary resection. We describe the clinical and pathologic features of this patient and review the characteristics of extrapulmonary IMTs with distant metastasis reported in the literature.