The pre-rRNA processing factor DEF is rate limiting for the pathogenesis of MYCN-driven neuroblastoma.

The nucleolar factor, digestive organ expansion factor (DEF), has a key role in ribosome biogenesis, functioning in pre-ribosomal RNA (pre-rRNA) processing as a component of the small ribosomal subunit (SSU) processome. Here we show that the peripheral sympathetic nervous system (PSNS) is very underdeveloped in def-deficient zebrafish, and that def haploinsufficiency significantly decreases disease penetrance and tumor growth rate in a MYCN-driven transgenic zebrafish model of neuroblastoma that arises in the PSNS. Consistent with these findings, DEF is highly expressed in human neuroblastoma, and its depletion in human neuroblastoma cell lines induces apoptosis. Interestingly, overexpression of MYCN in zebrafish and in human neuroblastoma cells results in the appearance of intermediate pre-rRNAs species that reflect the processing of pre-rRNAs through Pathway 2, a pathway that processes pre-rRNAs in a different temporal order than the more often used Pathway 1. Our results indicate that DEF and possibly other components of the SSU processome provide a novel site of vulnerability in neuroblastoma cells that could be exploited for targeted therapy.

Diagnostic and surgical challenge: middle ear dermoid cyst in 12 month old with branchio-oto-renal syndrome and multiple middle-ear congenital anomalies.

Described is the first case report, to our knowledge, of a middle-ear dermoid in a child with branchio-oto-renal (BOR) syndrome. Radiographic, pathologic, and intraoperative figures are shown. This was a diagnostic and surgical challenge as the presentation was similar to a congenital cholesteatoma and the child had numerous significant temporal bone abnormalities. After the intraoperative findings suggested a non-destructive process, the treatment strategy was altered. This case reiterates the need for a cautious, flexible operative approach in a syndromic child. Included is a relevant review of the literature and a detailed clinical analysis.

Comparative analysis of D2-40 and LYVE-1 immunostaining in lymphatic malformations.

Identification of lymphatic vessels in normal tissue and vascular malformations has been considerably enhanced by the recently discovered lymphatic endothelial markers D2-40 and LYVE-1. However, comparative analysis of these two antibodies in the evaluation of lymphatic malformations has not been widely reported. We evaluated twenty lymphatic malformations of skin/subcutis/soft tissue with immunostaining for D2-40 and LYVE-1. Ten high-power fields from each section were scored for total number of immunopositive vessels using identical fields with both markers. Vessels were grouped by diameter (< 225 microm and > 225 microm), with each vessel categorized according to the percentage of its lumen showing immunopositivity (< 25, 26-75, or > 75). Endothelial staining intensity was graded low or high in each case. We found no significant difference between total number of vessels stained with D2-40 or LYVE-1 or between the 2 markers in terms of the percentage of luminal circumference stained or intensity in vessels smaller than 225 microm. LYVE-1 stained a higher percentage of luminal circumference of channels greater than 225 microm at both low and high intensities. Large channels stained much less and sometimes not at all with either antibody. D2-40 and LYVE-1 are both effective for highlighting endothelium of lymphatic malformations, staining similar percentages of channels. LYVE-1 provides more luminal staining in channels larger than 225 microm but is less specific also staining macrophages and adipocytes. Both markers are expressed less strongly or sometimes not at all in large channels.

Vascular tumors of the heart in infants and children: case series and review of the literature.

Primary tumors of the heart are rare in children, of which vascular tumors comprise a small subgroup. We present the clinical, histopathologic, and imaging findings in six children with vascular tumors of the heart and review the findings of 36 previously published cases. We observed three intramuscular hemangiomas of the small-vessel type in older children, two congenital hemangiomas in infants, and one malignant polymorphous hemangioendothelioma. Intramuscular hemangiomas did not respond to corticosteroid and were biologically distinct from the congenital hemangiomas, both of which exhibited regression with pharmacotherapy. Age at diagnosis appears to predict histologic type, tumor location, and clinical presentation.

Cardiac, aortic, and pulmonary arteriopathy in HIV-infected children: the Prospective P2C2 HIV Multicenter Study.

Arteriopathy in human immunodeficiency virus (HIV)-infected patients is being increasingly recognized, especially in children. However, few studies have histologically evaluated the coronary arteries in HIV-infected children, and none have systematically assessed the aorta and pulmonary arteries. The coronary arteries, thoracic aorta, and the main and branch pulmonary arteries from the postmortem hearts of 14 HIV-infected children were systematically reviewed for vasculopathic lesions and compared with 14 age-matched controls. Findings from the HIV-infected children were compared with clinical, laboratory, and other postmortem findings. Coronary arteriopathy, seen in seven (50%) of the HIV-infected children, was primarily calcific, and it was associated with decreased CD3 and CD4 peripheral blood counts. Large vessel arteriopathy, seen in 9 (64%) of the 14 HIV-infected children, was primarily centered on the vasa vasorum and consisted mainly of medial hypertrophy and chronic inflammation. Large vessel lesions were associated with increased left ventricular mass z-scores (P = 0.02), and 78% of patients with large vessel arteriopathy had postmortem cardiomegaly. Coronary and large vessel arteriopathies are common in pediatric HIV-infection and have different clinicopathologic features suggesting different pathogenesis.

Diagnosis and management of MNGIE syndrome in children: case report and review of the literature.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) syndrome is a rare disorder that presents in childhood; however, marked delay in diagnosis is common. We report a case and review the literature describing the typical features that should alert pediatricians to the diagnosis. We also describe a novel management strategy for providing symptomatic relief.

BRD4 bromodomain gene rearrangement in aggressive carcinoma with translocation t(15;19).

Translocation t(15;19)(q13;p13.1) defines a lethal midline carcinoma arising adjacent to respiratory tract in young people. To characterize molecular alterations responsible for the distinctly aggressive biological behavior of this cancer, we mapped the chromosome 15 and 19 translocation breakpoints by fluorescence in situ hybridization (FISH) and Southern blotting. To evaluate preliminarily the frequency, anatomical distribution, and histological features of t(15;19) cancer, we developed a FISH assay for paraffin sections. Our findings reveal a novel oncogenic mechanism in which the chromosome 19 translocation breakpoint interrupts the coding sequence of a bromodomain gene, BRD4. These studies implicate BRD4 as a potential partner in a t(15;19)-associated fusion oncogene. In addition, we localized the chromosome 15 breakpoint to a 9-kb region in each of two cases, thereby identifying several candidate oncogenes which might represent the BRD4 fusion partner. FISH evaluation of 13 pediatric carcinomas revealed t(15;19) in one of four sinonasal carcinomas, whereas this translocation was not detected in thymic (n = 3), mucoepidermoid (n = 3), laryngeal (n = 2), or nasopharyngeal (n = 1) carcinomas. Our studies shed light on the oncogenic mechanism underlying t(15;19) and provide further evidence that this highly lethal cancer arises from respiratory mucosa.

Comparison of Pkd1-targeted mutants reveals that loss of polycystin-1 causes cystogenesis and bone defects.

A high level of polycystin-1 expression is detected in kidneys of all patients with autosomal dominant polycystic kidney disease (ADPKD). Mice that overexpress polycystin-1 also develop renal cysts. Whether overexpression of polycystin-1 is necessary for cyst formation is still unclear. Here, we report the generation of a targeted mouse mutant with a null mutation in Pkd1 and its phenotypic characterization in comparison with the del34 mutants that carry a 'truncation mutation' in Pkd1. We show that null homozygotes develop the same, but more aggressive, renal and pancreatic cystic disease as del34/del34. Moreover, we report that both homozygous mutants develop polyhydramnios, hydrops fetalis, spina bifida occulta and osteochondrodysplasia. Heterozygotes also develop adult-onset pancreatic disease. We show further that del34 homozygotes continue to produce mutant polycystin-1, thereby providing a possible explanation for increased immunoreactive polycystin-1 in ADPKD cyst epithelia in the context of the two-hit model. Our data demonstrate for the first time that loss of polycystin-1 leads to cyst formation and defective skeletogenesis, and indicate that polycystin-1 is critical in both epithelium and chondrocyte development.

Aggressive multimodal treatment of pleuropulmonary blastoma.

Pleuropulmonary blastoma is a rare intrathoracic neoplasm almost solely confined to childhood. Survival is poor. The authors report 2 children with extensive intrathoracic disease who are long term survivors after multimodal therapy. Both children received multiagent neoadjuvant chemotherapy, followed by surgical resection to remove all gross tumor. Postoperative chemotherapy was given to both children; radiotherapy was also given in the second case because of a question of positive tumor margins. Experience supports the use of multimodal therapy, including an aggressive surgical approach in the potentially curative treatment of this tumor.

Upper respiratory tract carcinoma with chromosomal translocation 15;19: evidence for a distinct disease entity of young patients with a rapidly fatal course.

BACKGROUND: Carcinoma of the upper respiratory tract is rare in childhood, and cytogenetic aberrations have not been characterized in this population. The chromosomal translocation 15;19 has been reported four times previously. All patients were young and had tumors arising in the thorax. The three reports that provide clinical follow-up all describe superior vena cava syndrome and death soon after presentation. All tumors were diagnosed as carcinoma (three undifferentiated, one mucoepidermoid), and the authors suggested thymus, lung, or germ cell origin. METHODS: The authors investigated the clinical and pathologic findings in two patients with poorly differentiated carcinoma showing evidence of t(15;19). This included a 13-year-old girl with a rapidly growing epiglottic mass, leading to superior vena cava syndrome and death and a 12-year-old girl with an aggressive nasopharyngeal mass showing intracranial extension. RESULTS: The laryngeal tumor was poorly differentiated, with vesicular nuclei, prominent nucleoli, extensive necrosis, and a lymphoplasmacytic infiltrate; cells were positive for cytokeratin and negative for lymphoma, melanoma, germ cell, and endocrine markers. Electron microscopy showed rare intermediate junctions and basal lamina. The nasopharyngeal tumor was poorly differentiated with areas of obvious squamous differentiation observed histologically, immunophenotypically, and ultrastructurally. Cytogenetic and fluorescent in situ hybridization studies were consistent with t(15;19)(q13;p13.1) in both cases. Both children received chemo- and radiotherapy. The first child died of disease after 36 weeks; autopsy revealed tumor in the larynx with spread to the skin/subcutis (neck and thorax) and lymph nodes (cervical, subcarinal, and pulmonary hilar). The second child developed widespread bony metastases and died of disease after 13 weeks. CONCLUSIONS: In conjunction with previous reports, the authors' findings show that t(15;19) is part of a distinct clinicopathologic entity characterized by young age, midline carcinoma of the neck or upper thorax, and a rapidly fatal course. Female gender and superior vena cava syndrome are common. The histogenesis of these distinctive tumors is unknown. The authors' findings suggest origin in the upper airway, perhaps from submucosal glands.

Primary renal neoplasms with the ASPL-TFE3 gene fusion of alveolar soft part sarcoma: a distinctive tumor entity previously included among renal cell carcinomas of children and adolescents.

The unbalanced translocation, der(17)t(X;17)(p11.2;q25), is characteristic of alveolar soft part sarcoma (ASPS). We have recently shown that this translocation fuses the TFE3 transcription factor gene at Xp11.2 to ASPL, a novel gene at 17q25. We describe herein eight morphologically distinctive renal tumors occurring in young people that bear the identical ASPL-TFE3 fusion transcript as ASPS, with the distinction that the t(X;17) translocation is cytogenetically balanced in these renal tumors. A relationship between these renal tumors and ASPS was initially suggested by the cytogenetic finding of a balanced t(X;17)(p11.2;q25) in two of the cases, and the ASPL-TFE3 fusion transcripts were then confirmed by reverse transcriptase-polymerase chain reaction. The morphology of these eight ASPL-TFE3 fusion-positive renal tumors, although overlapping in some aspects that of classic ASPS, more closely resembles renal cell carcinoma (RCC), which was the a priori diagnosis in all cases. These tumors demonstrate nested and pseudopapillary patterns of growth, psammomatous calcifications, and epithelioid cells with abundant clear cytoplasm and well-defined cell borders. By immunohistochemistry, four tumors were negative for all epithelial markers tested, whereas four were focally positive for cytokeratin and two were reactive for epithelial membrane antigen (EMA) (one diffusely, one focally). Electron microscopy of six tumors demonstrated a combination of ASPS-like features (dense granules in four cases, rhomboid crystals in two cases) and epithelial features (cell junctions in six cases, microvilli and true glandular lumens in three cases). Overall, although seven of eight tumors demonstrated at least focal epithelial features by electron microscopy or immunohistochemistry, the degree and extent of epithelial differentiation was notably less than expected for typical RCC. We confirmed the balanced nature of the t(X;17) translocation by fluorescence in situ hybridization in all seven renal tumors thus analyzed, which contrasts sharply with the unbalanced nature of the translocation in ASPS. In summary, a subset of tumors previously considered to be RCC in young people are in fact genetically related to ASPS, although their distinctive morphological and genetic features justify their classification as a distinctive neoplastic entity. Finally, the finding of distinctive tumors being associated with balanced and unbalanced forms of the same translocation is to our knowledge, unprecedented.

Giant cell angioblastoma: three additional occurrences of a distinct pathologic entity.

Giant cell angioblastoma was described previously in a single case report as a congenital soft-tissue tumor with a unique morphology. In the current report, we describe three cases of giant cell angioblastoma found in three infants; one case was congenital and located in the hand, one appeared neonatally in the palate, and one on the scalp of an infant. Clinical findings and results of light microscopy, immunohistochemistry, and electron microscopy were evaluated. All tumors were ulcerated; the hand and palate tumors also infiltrated soft tissue and bone. They exhibited a solid, nodular, and plexiform proliferation of oval-to-spindle cells with a frequent striking, concentric aggregation around small vascular channels. These cells had characteristics of undifferentiated mesenchymal cells, fibroblasts, myofibroblasts, and pericytes. Co-mingled with these cells were large mononuclear and multinucleate giant cells with histiocytic features. The palatal giant cell angioblastoma, excised with positive margins, was managed with interferon-alpha and showed no progression after nearly 5 years. The hand tumor diminished in size after management with interferon-alpha, was subtotally excised, and did not progress after 27 months. Follow-up data are unavailable for the patient with the scalp lesion. Our findings validate the classification of giant cell angioblastoma as a distinct and rare entity that is locally infiltrative but slow growing. The morphology and diverse cellular differentiation are consistent with an unusual form of neoplastic angiogenesis.

Gains of chromosome 8 are confined to mesenchymal components in pleuropulmonary blastoma.

Pleuropulmonary blastoma, an aggressive tumor that is emerging as a distinct entity of childhood, is characterized by mesenchymal elements (including undifferentiated blastema and often cartilaginous, rhabdomyoblastic, or fibroblastic differentiation) and epithelium-lined spaces. We investigated two patients with pleuropulmonary blastoma, a 3-year-old boy and an 11-year-old girl, both with large cystic masses replacing one lung. In both children, the post-chemotherapy resection specimens showed more maturation of rhabdomyoblasts and more nuclear pleomorphism in all mesenchymal cell lines, compared with biopsies sampled before treatment. Karyotypic analysis demonstrated gains in chromosome 8 in both cases and 17p deletion in one case. Fluorescent in situ hybridization analysis demonstrated that the chromosome 8 gains were present in all mesenchymal elements, including undifferentiated blastematous, rhabdomyoblastic, fibroblastic, and chondroblastic areas. Epithelial cells showed no chromosome 8 gains. The chromosome 8 aberrations were not appreciably different in pre- versus post-chemotherapy tissue. Our findings substantiate previous reports that polysomy of chromosome 8 is a consistent feature of pleuropulmonary blastoma. Further, they indicate that clonal proliferation in pleuropulmonary blastoma is restricted to the malignant mesenchymal elements, supporting the notion that the epithelial components of this tumor are non-neoplastic.

Expression pattern of T-cell-associated chemokine receptors and their chemokines correlates with specific subtypes of T-cell non-Hodgkin lymphoma.

Chemokine receptors mediate the migration of lymphocytes through the binding of soluble ligands, and their expression is differentially regulated in lymphocyte subsets. The pattern of chemokine receptor expression in T-cell non-Hodgkin lymphoma has not been previously studied. Using a panel of mouse monoclonal antibodies, we studied the immunohistochemical expression of the Th1-associated chemokine receptor CXCR3 in 141 patients with T-cell lymphoma, and we studied the receptors CCR4 and CCR5 and some of their ligands in a subset of these tumors. Expression of CXCR3 was typical of the smaller T cells in angioimmunoblastic lymphoma (15 of 18 patients), angiocentric lymphoma (3 of 3 patients), histiocyte-rich tumors (4 of 5 patients), and unspecified T-cell lymphomas (17 of 39 patients). CXCR3 expression was seen in only 1 of 15 patients with anaplastic lymphoma kinase (ALK)-positive anaplastic large-cell lymphoma. In contrast, all ALK-positive tumors showed diffuse reactivity for the Th2-associated receptor CCR4 (5 of 5 patients). CCR4 expression was also a consistent feature of the large-cell transformation of mycosis fungoides. CCR5 expression showed no consistent association with any T-cell tumor type. The chemokines Mig (CXCR3 ligand), TARC (CCR4 ligand), and MCP-2 (CCR5 ligand) were detected in intratumoral blood vessels and histiocytes. Mig was also coexpressed by a subset of CXCR3-positive tumor cells in 6 of 20 lymphomas. MCP-2 was highly expressed in stromal cells in 3 patients with nodal involvement by cutaneous T-cell lymphoma. As with normal T-cell subsets, we demonstrated that there is frequent differential expression of chemokine receptors in T-cell tumors, which may explain, in part, the distinctive patterns of spread in different tumor subtypes. (Blood. 2000;96:685-690)

Intraosseus teratoma of the iliac bone.

We present a 4-year-old child with a large iliac bone mass incidentally discovered in a plain abdominal radiograph. The pathological examination revealed a benign mature teratoma. To the best of our knowledge, the occurrence of intraosseous mature teratoma has not been previously reported. The child had had an immature teratoma of the neck discovered in a fetal ultrasound, and resected on day 6 of life. The neck teratoma recurred twice, at 16 months and at 3.5 years of age. In these two recurrences the lesion appeared progressively more mature. At the time of discovery of the iliac bone teratoma there was no evidence of residual neck disease. The radiological and pathological characteristics, differential diagnosis, and clinical course are discussed.

The detection of viral genomes by polymerase chain reaction in the myocardium of pediatric patients with advanced HIV disease.

OBJECTIVES: The aim of this study was to investigate the frequency of viral nucleic acid detection in the myocardium of human immunodeficiency virus (HIV)-infected children to determine whether an association exists with the development of heart disease. BACKGROUND: As improved medical interventions increase the life expectancy of HIV-infected patients, increased incidences of myocarditis and dilated cardiomyopathy (DCM) are becoming more apparent, even in patients without clinical symptoms. METHODS: Myocardial samples were obtained from the postmortem hearts of 32 HIV-infected children and from 32 age-matched controls consisting of patients with structural congenital heart disease and no myocardial inflammation and no cardiac or systemic viral infection. The hearts were examined histologically and analyzed for the presence of viral sequences by polymerase chain reaction (PCR) or reverse transcription-PCR. RESULTS: Myocarditis was detected histologically in 11 of the 32 HIV-infected patients, and borderline myocarditis was diagnosed in another 13 cases. Infiltrates were confined to the epicardium in two additional hearts. Virus sequences were detected by PCR in 11 of these 26 cases (42.3%); adenovirus in 6, CMV in 3 and both adenovirus and CMV in 2. Two cases without infiltrates were also positive for adenovirus: one had congestive heart failure (CHF) and the other adenoviral pneumonia. No other viruses were detected by PCR, including HIV proviral DNA. All control samples were negative for all viruses tested. CONCLUSIONS: These data suggest that the presence of viral nucleic acid in the myocardium is common in HIV-infected children, and may relate to the development of myocarditis, DCM or CHF and may contribute to the rapid progression of HIV disease.

Renal cell carcinomas in children and young adults: increased incidence of papillary architecture and unique subtypes.

Renal cell carcinomas in children and young adults are rare, and the pathologic features of these tumors have not been well described. We reviewed 24 renal cell carcinomas in children and young adults ages 6 to 29 years, 14 of whom were younger than 18 years of age. Fourteen were female. In 19 (79%) of 24 cases, the tumor met histologic criteria for papillary renal cell carcinoma, with at least 50% papillary architecture. Four of the remaining five cases were typical clear cell tumors in patients known to have von Hippel Lindau syndrome, and one case was of chromophobe type. In the papillary tumors, calcifications, high nuclear grade, extracapsular extension (American Joint Commission on Cancer stage T3), and lymph node metastases were common. Among these papillary tumors, four distinct histologic patterns could be identified. Collecting duct-like tumors (two cases) involved the large collecting ducts, were multifocal and predominantly papillary, and had focal tubular and solid areas. These tumors were reactive for epithelial membrane antigen (EMA) and keratins, including CK7, but negative for Ulex europeaus and high molecular weight keratin 34BE12. Voluminous cell tumors (four cases) were composed of cells with extremely voluminous clear cytoplasm and, although predominantly papillary, had areas that also resembled clear cell tumors. These tumors were reactive for keratins AE1/AE3 but were otherwise negative for all other keratins, EMA, and U. europeaus. One of these tumors showed an X;7 translocation. Adult type tumors (12 cases) resembled papillary tumors of adults. These tumors were reactive for EMA and keratins, including CK7, and all but one were negative for U. europeaus and keratin 34BE12. This last case had trisomies of chromosomes 7, 16, 17, and 20. The final neuroendocrinelike case was multifocal, organoid, and composed of nests of small cells in a neuroendocrinelike pattern. Three of 13 patients were alive with disease at last follow-up, and three additional patients died of disease, all within 2 years. Progression was highly associated with lymph node involvement at the time of resection. We conclude that the clinicopathologic features of renal cell carcinomas in children and young adults differ from those arising in older adults. These tumors are characteristically high-grade, high-stage, papillary tumors with numerous calcifications, and several subtypes can be identified based on histologic, immunohistochemical, and cytogenetic features. Some subtypes appear to be unique to this age group.