Role of FNAC in the Preoperative Diagnosis of Salivary Gland Lesions.

BACKGROUND: The characteristic cytologic features of the common salivary gland lesions have been well-delineated in literature. However, there also exist cytologic pitfalls and overlapping features that make an accurate diagnosis difficult in few cases. The present study was designed to compare the cytologic findings of salivary gland lesions with the histologic diagnoses, in order to assess the sensitivity, specificity and diagnostic accuracy of FNAC, with an emphasis on discordant cases. MATERIALS AND METHODS: Patients with suspected salivary gland enlargements, who were referred for FNAC, were included in this study, which was done over a 3 year period in a medical college hospital. FNAC was performed by using the standard procedure. Smears were stained by using Papanicolaou's and MGG stains. Cytologic diagnosis was compared with histopathologic diagnosis wherever it was available. RESULTS: Eighty eight patients with salivary gland swellings were included in the study. The ages of the patients ranged from 15 to 82 years, with the M:F ratio being 1.6:1. Out of 88 cases, 68 had swellings in parotid gland, 19 had them in submandibular gland and one had them in hard palate. Pleomorphic adenoma was the commonest neoplasm which was seen in our study. Mucoepidermoid carcinoma (MEC) was the only malignant lesion seen in our study. One each of Warthin's tumour (WT) and MEC were overdiagnosed and underdiagnosed respectively, the reason being squamous metaplasia in WT and subtle nature of malignant cells in low-grade MEC. CONCLUSION: WT and MEC can pose problems in cytologicdiagnosis. Sampling errors and interpretational errors can lead todiscordant diagnoses.

Practical value of MIB-1 index in predicting behavior of astrocytomas.

BACKGROUND: The MIB-1 labeling index (LI) has proved to be useful in assigning grading and prognosis to astrocytomas. The purpose of our study was to analyze the utility of MIB-1 LI in differentiating astrocytomas of varying grades and the possible relationships of MIB-1 LI with clinical parameters like age and sex. We also wanted to study the prognostic role of MIB-1 index in predicting behavior of astrocytomas. MATERIALS AND METHODS: Our study included 145 patients with astrocytic tumors of varying grades. Immunolabeling for all patients was done using MIB-1 antibody. Survival data could be obtained for 64 patients. A Mann-Whitney U test was used to test the difference in MIB-1 LI between different histological grades. The univariate analysis was done by the Kaplan-Meier method, and the multivariate analysis for survival was performed using the Cox proportional hazard model. RESULTS: Significant differences were noted in mean MIB-1 LI of high-grade and low-grade diffuse astrocytomas. MIB-1 LI did not vary significantly with age and sex. Univariate analysis showed favorable prognostic factors for low histopathological grade, young patient age and low MIB-1 LI; however, multivariate analysis showed that only histopathological grade had independent prognostic significance. CONCLUSIONS: Our study proves that MIB-1 LI is not dependent on factors like age and sex and is solely dependent on histological grade. Though the average level of MIB-1 LI varies considerably in the different grades of astrocytomas, considerable overlap can be observed between them. MIB-1 LI is a very useful adjunct to the histopathological diagnosis and can be of great help in situations where the clinical and radiological findings do not correlate with histological diagnosis.

The role of immunohistochemistry in predicting behavior of astrocytic tumors.

The purpose of this study was to analyze the significance of p53, bcl-2 and EGFR expression in the grading and biological behavior of astrocytic tumors, especially in the Indian population. A total of 117 cases of astrocytomas graded using the WHO grading system published in 2007 were immunolabeled using p53, EGFR and bcl-2 monoclonal antibodies and analyzed with respect to grade and other relevant parameters. The 117 cases included 16 cases of pilocytic astrocytomas and 25, 15 and 61 cases of diffuse fibrillary astrocytomas WHO grade II, anaplastic astrocytomas WHO grade III and glioblastomas (GBM), respectively. Our results showed that p53 alterations is an early event in astrocytic gliomagenesis, but is not significant in the evolution of pilocytic astrocytomas. Bcl-2 expression did not correlate with grade and no statistical correlation was seen with p53 expression. EGFR protein expression correlated with the severity of tumor grade. Of the GBM cases, 47.5% were p53 positive only, 18% were EGFR positive only, 16.5% were negative for both and 18% were positive for both. The mean age in the dual positive category was significantly higher when compared to the others. EGFR and p53 alterations are not mutually exclusive and might act synergistically to promote progression. We also noted a significantly higher p53 expression in females in GBMs. Though most of our findings correlated with those of previous studies, some differences were noted, especially in the pattern of immunoexpression in GBMs, perhaps because of ethnicity.