WHO Classification System (who + classification_system)

Distribution by Scientific Domains

Selected Abstracts

Traumatic injuries to permanent teeth in Turkish children, Ankara

Ceyhan Altun
From a total of 4956 children aged 6,12 years (mean age: 8.91 1.95) applying to the Center, 472 children (9.5%) were found to have suffered dental injuries during a period of 2 years. Injuries were classified according to drawings and texts based on the WHO classification system, as modified by Andreasen and Andreasen. Injury rates were highest among children age 6 and ages 8,10. The most frequently injured permanent teeth were the maxillary central incisors (88.2%), and the maxillary right central permanent incisor made up 47.2% of all injured teeth. The most common cause of dental trauma was falling while walking or running (40.3%). Most injuries involved a single tooth (64.8%). The most common type of injury was enamel fracture (44.6%). There was a significant difference in gender, where boys more often suffered from a dental hard tissue and pulp injury than girls (P = 0.019), whereas there was no difference in gender (P = 0.248) in the distribution of periodontal injuries. Injuries were found to occur more frequently during the summer (P < 0.001). Children with increased overjet were 2.19 times more likely to have dental injuries than other children. Considering that the incidence of traumatic dental injury is highest among children ages 6 and ages 8,10 as well as the fact that patients with increased overjet are more prone to dental trauma, preventive orthodontic treatment in early mixed dentition may play an important role in reducing traumatic dental injuries. [source]

Low grade diffuse gliomas: Shared cellular composition and morphometric differences

Sawako Kinjo
Low grade diffuse gliomas arising in the brain are challenging to treat because of their ability to infiltrate adjacent tissue. We attempted to clarify the cellular composition and histopathological features of low grade gliomas by utilizing morphometric and immunohistochemical analyses. Seventy-eight cases of low grade gliomas were examined including 21 diffuse astrocytomas (DA), 36 oligodendrogliomas (OL), and 21 oligoastrocytomas (OA), based on the WHO classification system. Moreover, OL were subdivided into three types based on the morphological characteristics advocated by Daumas-Duport et al.: OL type I, OL type II, and OL type III. The cellularity, nuclear form factor, and conditional entropy corresponding to the nuclear pleomorphism were measured in each sample by the image analysis software "Gunmetry." Twenty-two cases were immunohistochemically analyzed for the expression of several antigens. Morphometric data indicated that the cellularity of OL type II was significantly higher than that of DA, and that the conditional entropy of OL type III was significantly lower than that of DA. Although the results of the immunohistochemical studies were almost consistent with previous reports, there were significant differences in the expression of GFAP, nestin and p53 between DA and OL. Double immunostaining revealed that expression of Olig2 and GFAP, and Olig2 and nestin was mutually exclusive in most glioma cells. Moreover, the coexpression of nestin and GFAP occurred in DA and OA, but not in OL. We conclude that each glioma include cells expressing GFAP, cells expressing nestin, and cells expressing Olig2 in a characteristic proportion for each tumor type. We suggest that diffuse gliomas share cellular compositions in different ratios and that they can be distinguished by morphometrical analysis. [source]

The World Health Organization histologic classification system reflects the oncologic behavior of thymoma,

CANCER, Issue 3 2002
A clinical study of 273 patients
Abstract BACKGROUND Although the histologic classification of thymic epithelial tumors has been confusing and controversial, an agreement on the universal classification system for thymic epithelial tumors was achieved by the World Health Organization (WHO) in 1999. The authors previously reported that the WHO histologic classification system reflects invasiveness and immunologic function of thymic epithelial tumors. In this subsequent study, they examined the prognostic significance of this classification system. METHODS Clinical features as well as postoperative survival of patients with thymoma, but not thymic carcinoma, were examined with reference to WHO histologic classification based on an experience with 273 patients over a 44-year period. RESULTS There were 18 type A tumors, 77 type AB tumors, 55 type B1 tumors, 97 type B2 tumors, and 26 type B3 tumors. In patients with type A, AB, B1, B2, and B3 tumors, the respective proportions of invasive tumor were 11.1%, 41.6%, 47.3%, 69.1%, and 84.6%; the respective proportions of tumors with involvement of the great vessels were 0%, 3.9%, 7.3%, 17.5%, and 19.2%; and the respective 20-year survival rates were 100%, 87%, 91%, 59%, and 36%. According to the Masaoka staging system, the 20-year survival rates were 89%, 91%, 49%, 0%, and 0% in patients with Stage I, II, III, IVa, and IVb disease, respectively. By multivariate analysis, the Masaoka staging system and the WHO histologic classification system were significant independent prognostic factors, whereas age, gender, association with myasthenia gravis, completeness of resection, or involvement of the great vessels were not significant independent prognostic factors. CONCLUSIONS This study showed that histologic appearance reflects the oncologic behavior of thymoma when the WHO classification system is adopted. The WHO classification system may be helpful in clinical practice for the assessment and treatment of patients with thymoma. Cancer 2002;94:624,32. 2002 American Cancer Society. DOI 10.1002/cncr.10225 [source]

3463: Fusion oncogenes in adenoid cystic carcinoma

Purpose Adenoid cystic carcinomas of the salivary glands have a consistent t(6;9)(q22-23;p23-24) translocation. A recent study have shown that this results in fusion of the transcription factor gene MYB and the transcription factor gene NFIB which leads to activation of critical MYB target genes. The purpose of the study was to determine the expression of the MYB-NFIB fusion in lacrimal gland adenoid cystic carcinomas. Methods Primary lacrimal gland adenoid cystic carcinomas in Denmark during 1974-2007 were collected and classified according to the latest WHO classification system. The formalin-fixed paraffin-embedded tumours were analyzed using RT-PCR for detection of MYB-NFIB fusion transcript. 10 other non-adenoid cystic carcinomas of the lacrimal gland were also tested for the fusion. Results A total of 13 patients with a primary adenoid cystic carcinoma were identified in Denmark during the 33-year period. The median age at diagnosis was 41 years and the gender distribution was equal. Using RT-PCR the fusion transcript could be detected in five (38%) of the 13 cases. The fusion was the transcript variant MYB exon 14 linked to NFIB exon 8c in all five cases. None of the non-adenoid cystic carcinoma cases expressed the MYB-NFIB fusion. Conclusion The MYB-NFIB fusion is expressed in adenoid cystic carcinomas of the lacrimal gland. The result of the study supports the suggestion that the MYB-NFIB fusion is specific for adenoid cystic carcinoma. This is the first study to evaluate the frequency of the MYB-NFIB fusion in adenoid cystic carcinomas in the lacrimal gland. [source]

Non-invasive papillary urothelial neoplasms: The 2004 WHO/ISUP classification system

Hiroshi Miyamoto
The classification and grading of papillary urothelial neoplasms has been a long-standing subject of controversy. Previously, numerous diverse grading schemes for bladder tumor, including the 1973 World Health Organization (WHO) classification, existed whereby one of the major limitations was poor inter-observer reproducibility among pathologists. The WHO/International Society of Urological Pathology (ISUP) consensus classification system of urothelial neoplasms of the urinary bladder was developed in 1998 and was revised most recently in 2003 (published in 2004). Importantly, the current classification system provides detailed histological criteria for papillary urothelial lesions and allows for designation of a lesion (papillary urothelial neoplasm of low malignant potential) with a negligible risk of progression. Thus, the latest system is designed to be a universally acceptable one for bladder tumors that not only could be effectively used by pathologists, urologists, and oncologists, but also stratifies the tumors into prognostically significant categories. This article outlines the 2004 WHO/ISUP classification system regarding the specific histological criteria for non-invasive papillary urothelial neoplasms and the clinical significance of each category. [source]