524 research outputs found
Adrenocortical neoplasia: evolving concepts in tumorigenesis with an emphasis on adrenal cortical carcinoma variants
Adrenocortical carcinoma (ACC) is a rare, heterogeneous malignancy with a poor prognosis. According to WHO classification 2004, ACC variants include oncocytic ACCs, myxoid ACCs and ACCs with sarcomatous areas. Herein, we provide a comprehensive review of these rare subtypes of adrenocortical malignancy and emphasize their clinicopathological features with the aim of elucidating aspects of diagnostic categorization, differential diagnostics and biological behavior. The issue of current terminology, applied to biphasic tumors with pleomorphic, sarcomatous or sarcomatoid elements arising in adrenal cortex, is also discussed. We additionally present emerging evidence concerning the adrenal cortical tumorigenesis and the putative adenoma–carcinoma sequence as well
Asymptomatic lipofibroadenoma in a 17-year-old male:a case report and literature review of a rare entity
Background: The most common thymic tumours, thymomas, are derived from thymic epithelium and are generally low-grade neoplasm. Frankly malignant tumours, thymic carcinomas are rarer still. Exceedingly rare thymic tumours contain a mesenchymal tissue component such as fibrous connective tissue and/or mature fat. Lipofibroadenoma (LFA) is a very rare mixed epithelial-mesenchymal thymic tumour, included in the category of thymic epithelial tumors. LFA in addition to a mature adipocytic component, contains variable epithelial and mesenchymal tissue components. Owing to the presence of an epithelial component in LFA, this entity, in contrast to thymolipoma, is included in the World Health Organization (WHO) category of thymic epithelial neoplasm. Currently only 12 LFA cases have been described. The 12 previously reported cases all behaved in a benign fashion, although four cases were associated with a conventional type of thymoma. We here present a new, 13th, case of LFA. Case Description: The LFA was discovered incidentally in a previously healthy 17-year-old male after investigations for suspected pneumonia. On imaging a mass was discovered in the anterior mediastinum which was subsequently surgically removed. The resected tumour was extensively investigated, including the first instance of full molecular analysis of this rare entity and all available literature on LFA was sourced to provide a comprehensive overview. The histology of this LFA was similar to previously described cases. No gene mutations or rearrangements were identified. The patient made an uneventful recovery and after 13 months of follow-up remained well. Conclusions: An additional, 13th case of LFA is presented. Based on the available literature it appears that LFA may be considered a benign composite thymic tumour, although the combination of an additional conventional thymoma component may warrant closer follow-up.</p
Dynamics of the solar chromosphere. V. High-frequency modulation in ultraviolet image sequences from TRACE
We search for signatures of high-frequency oscillations in the upper solar
photosphere and low chromosphere in the context of acoustic heating of outer
stellar atmospheres. We use ultraviolet image sequences of a quiet center-disk
area from the Transition Region and Coronal Explorer (TRACE) mission which were
taken with strict cadence regularity. The latter permits more reliable
high-frequency diagnosis than in earlier work. Spatial Fourier power maps,
spatially averaged coherence and phase-difference spectra, and spatio-temporal
k-f decompositions all contain high-frequency features that at first sight seem
of considerable intrinsic interest but actually are more likely to represent
artifacts of different nature. Spatially averaged phase difference measurement
provides the most sensitive diagnostic and indicates the presence of acoustic
modulation up to f=20 mHz (periods down to 50 seconds) in internetwork areas.Comment: 9 pages, 8 figure
Effect of oxygen on the expression of hypoxia-inducible factors in human fetal lung explants
Background: Fetal lung development requires proper coordination between lung epithelial and vascular morphogenesis. A major determinant in lung vascular development is vascular endothelial growth factor (VEGF), which is regulated by hypoxia-inducible factors (HIFs). VEGF is expressed in the airway epithelium, while its receptors (VEGFRs) are expressed in the pulmonary mesenchyme. The hypoxic environment in utero is beneficial for fetal organogenesis, especially vascular development. However, little is known about the expression of HIFs and VEGFR-2 in the human fetal lung in vitro. Objectives: The purpose of this study was to investigate the effects of hypoxia on fetal lung morphology and mRNA expression of VEGF, VEGFR-2, HIF-2α, and HIF-3α. Methods: An explant culture technique was used to study the effects of normoxic and hypoxic conditions on human fetal lung. Results: The morphology remained largely unchanged in explants cultured under hypoxic or normoxic conditions. Quantitative RT-PCR showed that the mRNA expression of VEGF-A, but not VEGFR-2 is upregulated in explants cultured at 1.5% compared with 21% oxygen. We observed a nonsignificant increase in HIF-2α and HIF-3α mRNA expression in explants cultured at 1.5% oxygen. These data suggest that the mRNA expression of VEGF, and possibly HIF-2α and HIF-3α, is regulated by hypoxia in the developing human lung. Conclusion: This lung explant culture model appears to be a valuable model to unravel the molecular mechanisms of human lung development
Renal Tumors of Childhood—A Histopathologic Pattern-Based Diagnostic Approach
Renal tumors comprise approximately 7% of all malignant pediatric tumors. This is a
highly heterogeneous group of tumors, each with its own therapeutic management, outcome, and
association with germline predispositions. Histopathology is the key in establishing the correct
diagnosis, and therefore pathologists with expertise in pediatric oncology are needed for dealing with
these rare tumors. While each tumor shows different histologic features, they do have considerable
overlap in cell type and histologic pattern, making the diagnosis difficult to establish, if based
on routine histology alone. To this end, ancillary techniques, such as immunohistochemistry and
molecular analysis, can be of great importance for the correct diagnosis, resulting in appropriate
treatment. To use ancillary techniques cost-effectively, we propose a pattern-based approach and
provide recommendations to aid in deciding which panel of antibodies, supplemented by molecular
characterization of a subset of genes, are required
Clinical and Molecular Characteristics and Outcome of Cystic Partially Differentiated Nephroblastoma and Cystic Nephroma: A Narrative Review of the Literature
In children presenting with a predominantly cystic renal tumor, the most likely diagnoses
include cystic partially differentiated nephroblastoma (CPDN) and cystic nephroma (CN). Both
entities are rare and limited information on the clinical and molecular characteristics, treatment, and
outcome is available since large cohort studies are lacking. We performed an extensive literature
review, in which we identified 113 CPDN and 167 CN. The median age at presentation for CPDN
and CN was 12 months (range: 3 weeks–4 years) and 16 months (prenatal diagnosis–16 years),
respectively. No patients presented with metastatic disease. Bilateral disease occurred in both entities.
Surgery was the main treatment for both. Two/113 CPDN patients and 26/167 CN patients had
previous, concomitant, or subsequent other tumors. Unlike CPDN, CN was strongly associated with
somatic (n = 27/29) and germline (n = 12/12) DICER1-mutations. Four CPDN patients and one CN
patient relapsed. Death was reported in six/103 patients with CPDN and six/118 CN patients, none
directly due to disease. In conclusion, children with CPDN and CN are young, do not present with
metastases, and have an excellent outcome. Awareness of concomitant or subsequent tumors and
genetic testing is important. International registration of cystic renal tumor cohorts is required to
enable a better understanding of clinical and genetic characteristics
Cancer-prone syndrome of mosaic variegated aneuploidy and total premature chromatid separation: Report of five infants
Five infants (two girls and three boys) from four families all had severe pre- and post-natal growth retardation, profound developmental delay, microcephaly, hypoplasia of the brain with Dandy-Walker complex or other posterior fossa malformations, and developed uncontrollable clonic seizures. Four infants developed Wilms tumors, and one showed cystic lesions in bilateral kidneys. All five infants showed variegated mosaic aneuploidy in cultured lymphocytes. In two infants whose chromosomes were prepared by us, 48.5%-83.2% lymphocytes showed total premature chromatid separation (PCS). Their parents had 3.5%-41.7% of their lymphocytes in total PCS. The remaining three infants and their parents, whose chromosomes were prepared at outside laboratories, tended to show lower frequencies of total PCS. Another five infants reported with the disorder were reviewed together with the five infants we described. Together, their clinical and cytogenetic manifestations were similar enough to suggest a syndrome. Seven of the 10 infants developed proven or probable Wilms tumors. The age at diagnosis of the tumors was younger than usual at 2-16 months. The tumors were bilateral in four infants and unilateral in three infants, and cystic changes were present in six infants. Two infants developed botryoid rhabdomyosarcoma. The carriers of the syndrome are thus liable to tumorigenesis. The possible role of mitotic checkpoint defects, proven in two infants with the syndrome (Matsuura et al. [2000: Am J Hum Genet 69:483-486]), was discussed in connection with tumor development and progression
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