Congenital mesoblastic nephroma: a study of 19 cases using immunohistochemistry and ETV6-NTRK3 fusion gene rearrangement.

Mesoblastic nephroma (MN) is the most common renal tumour in the first 3 months of life and accounts for 3-5% of all paediatric renal neoplasms. To further understand the morphological variants of MN, we identified 19 cases of MN (five classic, eight cellular and six mixed) and examined each case for markers known to be important in urogenital embryological development (PAX8, WT1 and RCC), stem cell associated markers (Oct 4, CD34 and c-kit), muscle/myofibroblastic markers (muscle specific actin, calponin and h-caldesmon), aberrant transcription factors, cell cycle regulation and other oncogenic proteins (p16, cyclin D1 and beta-catenin). Fluorescence in situ hybridisation (FISH) testing for ETV6-NTRK3 gene fusion/rearrangement revealed further differentiation between the subtypes with ETV6-NTRK3 gene fusion detected in 0/5 of the classic MN, 8/8 of the cellular MN and 5/6 of the mixed MN cohorts, respectively.

Xeroderma pigmentosa: three new cases with an in depth review of the genetic and clinical characteristics of the disease.

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder characterized by hypersensitivity of the skin and eyes to UV-radiation as a result of a defect in one of eight genes. Seven genes (XPA-XPG) have a defect in Nucletoide Excision Repair (NER), while the eighth gene XPV has a defect in polymerase η, which is responsible for replication of UV-damaged DNA to produce corrected daughter strands. We present the varied clinical courses of three African-American female patients with XP.

Noniatrogenic neonatal gastric perforation: the role of interstitial cells of Cajal.

Noniatrogenic neonatal gastric perforation is a rare and life-threatening condition whose etiology is often unclear. Interstitial cells of Cajal act as gastrointestinal pacemaker cells and express the proto-oncogene c-Kit. Six new cases were identified at our institution which presented with no mechanical, pharmacologic, or otherwise medical-related intervention prior to rupture.

Epstein-Barr virus associated smooth muscle tumors in post transplant pediatric patients two cases of rare locations, and review of the literature.

Epstein-Barr virus (EBV) may present few or no symptoms in immunocompetent individuals; however, in immunocompromised patients as in the case of AIDS and post-transplant patients, the virus occasionally stimulates neoplastic transformations. Epstein-Barr virus may play a role in the development of smooth muscle tumors (SMT). In the case of Epstein-Barr associated smooth muscle tumors (EBV+SMT), the virus is thought to be the leading factor to the tumorigenic pathway.

Usefulness of OCT4/3 immunostain in pediatric malignant germ cell tumors.

Octamer4/3 is a POU transcription factor that regulates pluripotentiality in embryonic stem and germ cells and primordial germ cells. When expressed in post-embryonic life, Octamer4/3 may lead to malignant germ cell tumors (GCT). Thirty samples were selected for this study (26 GCT samples and 4 cryptorchid testes samples) and 16 non-GCT were used as controls.

Unusual presentation of extracardiac fetal rhabdomyoma of the larynx in a pediatric patient with tuberous sclerosis.

Tuberous sclerosis (TSC) is an autosomal-dominant genetic disease characterized by a spectrum of pathologic manifestations involving skin, brain, kidney, and heart. These manifestations include neuroectodermal, mesodermal, and skin lesions as well as a variety of associated tumors and hamartomas. We report an 11-year-old male with previously diagnosed TSC who presented with a laryngeal mass shown on histology to be fetal cellular rhabdomyoma.

The spectrum of pulmonary malformation in trisomy-21 patient. A review with emphasis on the molecular-genetic basis.

Gene overexpression has been identified as a primary determining factor for the distinct Down syndrome (DS) phenotypes. Previous genetic research has identified a spectrum of gene expressions responsible for many of the observed traits in DS patients including cardiovascular, brain, and GI anomalies. However, the molecular/genetic basis underlying pulmonary anomalies are yet to be identified, even though respiratory complications represent the leading cause of morbidity and mortality in DS patients.

Nephrogenic rest within a lipomyelomeningocele in a patient with unilateral renal agenesis.

Nephrogenic rests (NR) are foci of embryonal renal tissue that persist beyond the normal period of renal morphogenesis. They are commonly found in kidneys bearing Wilms tumor but may also rarely occur in different locations. Nephrogenic rests have been reported in the lumbosacral area in a total of nine cases, including our case.

Splenic cysts in the pediatric population: a report of 21 cases with review of the literature.

Splenic cysts are rare lesions that can occur in parasitic and non-parasitic forms. Because they are uncommon, the classification, pathogenesis, and management techniques are still debated. The continual review of splenic cyst cases in the pediatric population is essential for establishing a clear diagnosis and course of treatment.