Fluorescence in situ hybridization in the definitive diagnosis of malignant mesothelioma in effusion cytology.

BACKGROUND: Distinction of malignant mesothelioma (MM) from reactive mesothelial cells (RM) in effusions is notoriously difficult. The aim of our study was to test chromosomal aberrations detected by fluorescence in situ hybridization (FISH) in the diagnosis of MM in effusion cytology and to explore the potential role of p16, p14, and p15 gene methylation as an alternative mechanism of tumor suppressor gene inactivation. METHODS: Fifty-two effusions of biopsy-proven MM and 28 benign effusions were retrospectively analyzed by multitarget FISH assay for aberrations of chromosomes 3, 7, 17, and 9p21. In case of a negative result, the corresponding MM biopsy specimen was analyzed. Methylation-specific polymerase chain reaction (MSP) for p16, p14, and p15 was performed on FISH-negative MM biopsy specimens. RESULTS: Seventy-nine percent of effusions with biopsy-proven MM had chromosomal aberrations, with loss of 9p21 as the most common finding. All benign effusions were FISH negative. Sensitivity, specificity, and positive and negative predictive values for detection of MM by FISH were 79%, 100%, 100%, and 72%, respectively. Six of nine FISH-negative effusions with biopsy-proven MM were also FISH negative in the MM biopsy specimens. Four of five FISH-negative biopsy specimens showed promoter methylation in p16 and p14 as compared with one of 12 benign controls. CONCLUSIONS: FISH is a sensitive and highly specific method for the definitive diagnosis of MM in effusion cytology. In the subset of FISH-negative MM, tumor suppressor genes on the chromosomal region 9p21 are often inactivated by promoter methylation.

Parotid tumors: fine-needle aspiration and/or frozen section.

OBJECTIVE: The purpose of this study was to analyze and compare the value of fine-needle aspiration cytology (FNAC) and frozen section (FS) analysis in the assessment of parotid gland tumors. STUDY DESIGN: Chart review and cross-sectional analysis. SUBJECTS AND METHODS: FNAC and FS analysis of 110 parotid tumors, 68 malignancies and 42 benign tumors, were analyzed and compared with the final histopathologic diagnosis. RESULTS: The accuracy, sensitivity, and specificity of FNAC in detecting malignant tumors were 79 percent, 74 percent, and 88 percent, respectively. On FS analysis, the accuracy, sensitivity, and specificity in detecting malignant tumors were 94 percent, 93 percent, and 95 percent, respectively. The histologic tumor type was correctly diagnosed by FNAC and FS in 27 of 42 (64%) and 39 of 42 (93%) benign tumors, respectively, and in 24 of 68 (35%) and 49 of 68 (72%) malignant neoplasms, respectively. CONCLUSION: The current analysis showed a superiority of FS compared with FNAC regarding the diagnosis of malignancy and tumor typing. FNAC alone is not prone to determine the surgical management of parotid malignancies.

Diagnostic accuracy of fine-needle aspiration cytology and frozen section in primary parotid carcinoma.

BACKGROUND: The low incidence and histologic heterogeneity of primary parotid carcinomas makes it difficult to evaluate the value of preoperative fine-needle aspiration cytology (FNAC) and intraoperative frozen section (FS) analysis. In the current study, the authors reviewed a single institution's experience regarding the preoperative and intraoperative diagnostic value of FNAC and FS in primary salivary gland carcinomas. METHODS: Between January 1990 and December 2002, 108 primary parotid carcinomas were resected at the Department of Otorhinolaryngology, Head and Neck Surgery at the University of Berne, Inselspital (Berne, Switzerland). Included in the study were a total of 101 carcinomas with preoperative FNAC results in 88 tumors and/or intraoperative FS results in 45 tumors. In a retrospective study, the results of FNAC and FS were analyzed and compared with the corresponding histopathologic diagnoses. RESULTS: The cytologic findings were true-positive for malignancy in 63 tumors (72%), false-negative in 22 tumors (25%), and nondiagnostic in 3 tumors (3%). The tumor grading was correct in 29 of 63 tumors (46%), and the exact tumor typing was correct in 27 of 63 (43%) true-positive tumors. The FS findings were true-positive for malignancy in 43 of 45 tumors (96%), the tumor grading was correct in 35 of 45 tumors (78%), and the tumor typing was correct in 32 of 45 tumors (71%). Overall, at the time of surgery, of the 101 parotid carcinomas, the tumor was known to be malignant in 83 tumors (82%), and the correct grade and the exact tumor type were known in 55 tumors (54%) and 48 tumors (48%), respectively. CONCLUSIONS: FNAC recognized malignancy in 72% of tumors, but it could not be relied upon to provide an accurate tumor grading or typing. Therefore, FNAC alone is not prone to determine the surgical management of primary parotid carcinomas. The current analysis showed the statistically significant superiority of FS compared with FNAC regarding the diagnosis of malignancy, tumor grading, and tumor typing in primary parotid carcinomas.