Alterations of cell cycle regulators affecting the RB pathway in nonfamilial retinoblastoma.

We undertook the present study to examine alterations affecting the RB pathway in the G1 checkpoint and to determine their potential clinical significance in children affected with nonfamilial retinoblastoma. Using immunohistochemistry, patterns of expression of pRB, p16/INK4A, and E2F1 were analyzed in tissue from a cohort of 86 well-characterized patients with nonfamilial retinoblastoma diagnosed at the "Instituto Nacional de Pediatria" in Mexico City. The relationship of these phenotypes to proliferative index was assessed by analysis of Ki67 antigen expression. pRB expression was found in 11 (13%) cases. Using a hypophosphorylated specific pRB antibody, we observed low levels of underphosphorylated pRB expression in only 1 of 9 evaluable positive cases. These data suggest that the detected pRB products were hyperphosphorylated and thus had decreased functional activity. Increased p16 nuclear expression was found in only 6 tumors. No tumors showed deletions or mobility shifts of the INK4A gene. Undetectable pRB levels were significantly associated with undetectable p16 expression (odds ratio, 10.8; 95% confidence interval, 1.4-81.3; P =.03). All tumors showed nuclear immunoreactivities for E2F1 and Ki67. Increased Ki67 proliferative index was associated with increased staining for E2F1 (r =.44; P =.008) and increasing clinical stage (P =.03). Among children with unilateral disease, the mean Ki67 proliferative index was significantly higher in children with advanced clinical disease (stages 3 and 4) (mean 81.25; SD 6.78) than in those with earlier stage disease (mean 69.50; SD 9.45) (P = 0.001). Among children with bilateral disease, however, the mean proliferative index was not significantly higher for children with advanced clinical stage. When examining all cases together, there was a significant trend toward increasing proliferative index with increasing clinical stage (P =.03). In unilateral tumors, we also found that presence of detectable pRB was associated with a lower percentage of cells expressing E2F1 (46.7% v 70.8%) (P = 0.05), whereas there was no association between presence of pRB and E2F1 among bilateral tumors. We have found that expression of some of the cell cycle markers examined varies according to laterality, suggesting underlying differences in the capacity for cell cycle regulation between these 2 forms of the disease. Differences in capacities for cell cycle regulation may account for some differences in clinical behavior. Thus, the inclusion of molecular markers may become useful adjuncts to clinicopathological staging and subsequent determination of therapy.

Presence of human papilloma virus in tumor tissue from children with retinoblastoma: an alternative mechanism for tumor development.

Epidemiological studies have shown that the use of barrier methods of contraception is associated with a decreased incidence of papilloma virus infection and reduced risk of having a child with retinoblastoma. Thirty-nine primary retinoblastomas were analyzed for the presence of papilloma virus sequences. Tumor tissue sections were also used to assess the expression of the retinoblastoma protein and proliferative index. Papilloma sequences were detected in 14 of 39 (36%) tumors. Tumors in which viral sequences were detected were associated with a lower proliferative index (68% versus 78%; P = 0.015). Children with tumors containing viral sequences had a lower risk of extraocular disease (odds ratio, 9.0; 95% confidence interval, 1.6-49; P = 0.008) and a lower birth weight (2.9 versus 3.5 kg; P = 0.030). Based on these data, it is our hypothesis that papilloma viruses may play a role in the development of sporadic retinoblastoma. Detection of papilloma virus sequences and retinoblastoma protein in certain primary lesions suggests an alternative mechanism of tumor development for sporadic retinoblastoma.

Elejalde syndrome--a melanolysosomal neurocutaneous syndrome: clinical and morphological findings in 7 patients.

BACKGROUND: Silvery hair and severe dysfunction of the central nervous system (neuroectodermal melanolysosomal disease or Elejalde syndrome) characterize this rare autosomal recessive disease. Main clinical features include silver-leaden hair, bronze skin after sun exposure, and neurologic involvement (seizures, severe hypotonia, and mental retardation). Large granules of melanin unevenly distributed in the hair shaft are observed. Abnormal melanocytes and melanosomes and abnormal inclusion bodies in fibroblasts may be present. Differential diagnosis with Chédiak-Higashi syndrome and Griscelli syndrome must be done. OBSERVATIONS: We studied pediatric patients with silvery hair and profound neurologic dysfunction. Immune impairment was absent. Age of onset of neurologic signs ranged from 1 month to 11 years; the signs included severe muscular hypotonia, ocular alterations, and seizures. Mental retardation since the first months of life was noted in 4 cases. Psychomotor development was normal in 3 cases, but suddenly the patients presented with a regressive neurologic process. Four patients died between 6 months and 3 years after the onset of neurologic dysfunction. One patient showed characteristic ultrastructural findings of Elejalde syndrome. CONCLUSIONS: Elejalde syndrome is different from Chédiak-Higashi and Griscelli syndrome and is characterized by silvery hair and frequent occurrence of fatal neurologic alterations. Psychomotor impairment may have 2 forms of presentation: congenital or infantile. Although Elejalde syndrome and Griscelli syndrome are similar, the possibility that they are 2 different diseases, although probably allelic related, is suggested.

Validation of the verbal autopsy method to ascertain acute respiratory infection as cause of death.

The validity of the Verbal Autopsy (VA) in death due to acute respiratory infection (ARI), was tested in 36 children who died by any acute infectious disease as stated by the necropsy diagnosis, at two public hospitals in Mexico City; the illness started at home. Clinical data obtained through VA were compared with diagnoses of necropsies, which were considered as "gold standard". The presence of dyspnoea for more than one day showed sensitivity of 0.69 and specificity of 0.74, while history of coughing showed a sensitivity of 0.61 and a specificity of 0.73. Combination of both clinical data improved specificity (0.83), but decreased sensitivity (0.54). Additional sources of diagnosis (a panel of assessors, the clinical record and the death certificate), also showed good sensitivity (0.69-0.77) and specificity (0.74-7.8). Focus on history of dyspnea and/or cough in children with an infectious syndrome should be emphasized, as a useful epidemiologic tool to determine children's mortality due to ARI in areas where diagnosis resources are constrained.

Opportunistic infections in pediatric HIV infection: a study of 74 autopsy cases from Latin America. The Latin American AIDS Pathology Study Group.

The present report describes opportunistic infections found at 74 autopsies of pediatric HIV/AIDS patients performed at several hospitals in Latin American countries. Fungal infections were the most common (53 cases), Candida sp. (39.18%) and Pneumocystis carinii (20.27%) being the most frequently recognized. Other fungal diseases included histoplasmosis, aspergillosis, and cryptococcosis. Viral infections were present in 31 cases, 38.7% being due to cytomegalovirus. Other viruses recognized included herpes simplex and adenovirus. Additional opportunistic infections were due to Mycobacterium avium-intracellulare, toxoplasmosis, and tuberculosis. Nonspecific bacterial bronchopneumonia was present in 11 cases. Cytomegalovirus and P. carinii coinfection was the most common association found. In this series patients died at a younger age (72% at or younger than 1 year old) and there was a slightly higher number of cases of histoplasmosis and brain toxoplasmosis than in other previously published series of infants and children.

Edematous, scarring vasculitic panniculitis: a new multisystemic disease with malignant potential.

BACKGROUND: Hydroa vacciniforme (HV) is a disease of unknown origin characterized by erythema, vesicles, necrosis, and varicelliform scars in light-exposed skin. Systemic involvement is absent. A few patients have been reported with "severe HV" with systemic involvement, development of non-Hodgkin's lymphoma, and a poor prognosis. OBJECTIVE: Our purpose was to characterize and differentiate our patients' disease from HV. METHODS: We performed a retrospective clinicopathologic study of 14 children previously diagnosed as having "severe HV." RESULTS: The extension and severity of the cutaneous lesions, fever, wasting, failure to thrive, hepatosplenomegaly, vasculitis, panniculitis, and potential development of lymphoma are features that clearly differentiate edematous scarring vasculitic panniculitis from HV. CONCLUSION: Edematous scarring vasculitic panniculitis is a novel multisystemic disease with malignant potential that is not related to classic HV.

[Tuberous sclerosis. Early diagnosis with autonomic nervous system responses in hypopigmented skin]. / Esclerosis tuberosa. Diagnóstico precoz mediante respuestas de sistema nervioso autónomo en piel hipopigmentada.

The earliest clinical sign for the diagnosis of tuberous sclerosis (TS) is the presence of cutaneous hypopigmented macules. However, there are no clinical, histopathological or functional criteria to discriminate between hipopigmented macules of TS and those without associated pathology. In this prospective study, the responses of the autonomous nervous system, erythema and sweating induced through iontophoresis with pilocarpine, were studied in three groups of patients (20 with TS, 10 with hipomelanosis of Ito, and 10 with hipopigmented macules without associated pathology). In hipopigmented macules without associated pathology, the responses were similar to those observed in normal skin. In TS erythema and sweating were significantly diminished (p = < 0.001). In hypomelanosis of Ito the decrease in erythema and sweating were not statistically significant. In TS the degree of decrease of erythema and sweating correlated positively with the severity of the neurological alterations. Light and electronmicroscopic studies of the hypopigmented macules in the three groups showed morphologically normal sweat glands and nerves. The latter suggests a disfunction of the sweat glands in TS as a cause of their abnormal behavior. We conclude that sweat testing in hypopigmented macules is a useful mean for the early diagnosis of ET.

Malignant cutaneous tumors in children. Twenty years of experience at a large pediatric hospital.

The frequency of different malignant cutaneous tumors (MCTs), primary and metastatic, in children is not known. We reviewed all MCTs, primary and metastatic, seen during a 20-year period in a large general pediatric hospital. Fifty-three MCTs, 36 primary and 17 metastatic, were diagnosed in 36,207 pediatric dermatology patients. The incidence was 1.4 per 1000 patients. The relative frequency of occurrence of the different tumors was as follows: rhabdomyosarcoma, 25%; lymphomas, 19%; basal cell carcinoma, 13%; leukemia, 13%; neuroblastoma, 10%; malignant melanoma, 6%; squamous cell carcinoma, 6%; unclassified sarcomas, 4%; epithelioid schwannoma, 2%; ependymoma, 2%. The mean follow-up was 3 years; 48% died, 27% were lost to follow-up, and 25% are under control. We conclude that primary and metastatic MCTs in children are rare. Their types differ from MCTs in an older age population. MCTs in children are associated with a high mortality rate, often related to late recognition.

Detection of the cystic fibrosis delta-F508 mutation at autopsy by site-directed mutagenesis.

In Caucasian populations cystic fibrosis (CF) is the most common autosomal recessive disorder. CF was previously considered rare in Mexico; however, the reported frequency is about 1% in autopsies. This discrepancy appears to be due to the inability to diagnose the illness during life. It is now known that in developing countries a great number of affected children die without the benefit of CF diagnosis and appropriate treatment. In this study we have used the PCR-mediated site-directed mutagenesis technique for the detection of the delta-F508 mutation in a 6-month-old Mexican boy who died without definitive diagnosis. The tissue available from the child was a formaldehyde fixed paraffin-embedded liver. We identified the delta-F508 mutation in homozygous form in the propositus and in a heterozygous form in his parents. This represents the first report of CF molecular diagnosis in Mexico.

[The liver biopsy: a tool for the diagnosis in chronic cholestasis in pediatric liver disease]. / La biopsia hepática por punción en el diagnóstico diferencial de la colestasis prolongada en lactantes.

Protracted cholestasis of infancy is a clinical and pathological manifestation of several injuries to the liver and biliary tract. Function liver biopsy is a well stablished procedure for cholestasis differential diagnosis which allows to guide therapeutics. In this review the author describe and analyse biopsy advantages and mention some of the technical and methodological considerations which permit to improve histological diagnosis. Preliminary results of a study of 110 punction liver biopsies from patients with neonatal protracted cholestasis are presented. In 42 patients a biliary atresia was found and a correlation with surgical findings was done. A 94% sensitivity, and 97% specificity for histological diagnosis was found. In contrast, gammagraphic diagnosis had a 100% sensitivity and only 77.7% specificity. In 16 patients, from a total of 38 with a final diagnosis of neonatal hepatitis, a biliary obstruction was initially suspected. In these 16 patients, a punction liver biopsy was not considered before the surgical exploration. However, a clear histological picture of neonatal hepatitis was found in the wedge liver biopsy obtained during abdominal laparotomy. This data confirms punction liver biopsy utility even if a highly suggestive clinical picture of biliary obstruction is found. It also allows to avoid unnecessary exploratory laparatomy.

[Infectious hepatitis. I. Presence of HBs antigen]. / Hepatitis infecciosa. I. Presencia del antígeno HBs

A prospective study in 268 patients of different pediatric ages affected with icteric hepatitis is presented, with a longitudinal follow-up of one year minimum. Different types of clinical evolution are described and related to the presence of HBs antigen. In 34 of the 268 patients HBs antigen was positive; in 20 of 28 patients with acute and long evolution, positivity of the antigen was transitory with an average of 46 days; in the remaining 8 of 28 patients it extended from 6 months to less than 2 years. The presence of HBs antigen is a risk that may be correlated with the tendency to extend the prolonged.

Diffuse dermographic mastocytosis without visible skin lesions.

The case is presented of a 3-year-old girl with urticaria and pressure dermographism. The condition began the age of one year. A skin biopsy confirmed the suspected diagnosis of diffuse mastocytosis. The identification of the form of mastocytosis without skin lesions and with dermographism and pressure urticaria as its only signs is important. It should be considered in any chronic urticaria appearing at birth or in an early age which is unresponsive to the usual symptomatic medication.