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BACKGROUND: Synovial sarcoma (SS) is characterized by the t(X; 18) (p11.2; q11.2) translocation resulting in the SYT-SSX fusion transcript, detectable by reverse transcriptase polymerase chain reaction (RT-PCR). Fine-needle aspiration (FNA) cytology diagnosis of SS is challenging. We evaluated the applicability of RT-PCR on FNAs and to perform a detailed cytomorphological analysis in unequivocal cases of SS. METHODS: A prospective and retrospective analysis was performed over 4 years (2003-2007). Prospectively, FNAs positive for the SYT-SSX fusion transcript by RT-PCR (n = 6) and, retrospectively, cases proven on histopathology and immunohistochemistry (ICC; positivity for vimentin and epithelial membrane antigen [EMA]/cytokeratin) as SS (n = 10) were included in the study. A detailed cytomorphological analysis was carried out. RESULTS: There were 9 biphasic and 7 monophasic tumors. The aspirates from both biphasic and monophasic tumors were richly cellular in all cases with micro tissue fragments. Pericapillary arrangement of tumor cells was present in most cases. Attempted gland formation was seen in 7 of 9 biphasic tumors. The individual tumor cells were round, ovoid, or spindle shaped. Pleomorphism was mild; monophasic tumors displayed lesser pleomorphism as compared with the biphasic ones. Nuclear chromatin was bland in all cases except 1 and nucleolar prominence was seen in just 3 biphasic tumors. Mast cells were seen in 3 biphasic and 2 monophasic tumors. Scanty to moderate extracellular matrix material was seen in 5 cases. CONCLUSIONS: FNA cytology of SS shows a spectrum of cytomorphological features; the diagnosis is confirmed by RT-PCR on the aspirated material for the SYT-SSX fusion transcript. Cancer (Cancer Cytopathol) 2009. © 2009 American Cancer Society.

Aim: To determine whether F-18-fluorodeoxyglucose positron emission tomography (F-18-FDG PET) can be used to differentiate among common enhancing brain tumors such as gliomas, metastatic brain tumors, and lymphoma. Materials and Methods: We evaluated 20 patients with an enhancing brain tumor on magnetic resonance imaging (MRI). FDG PET scan was done in all patients pre operatively. For PET image analysis, regions of interest were placed over the tumor (T), contralateral cortex (C), and white matter (WM). Average and maximum pixel values were determined at each site. On the basis of these measurements, average and maximum standard uptake values (SUV avg and SUV max ) were calculated, and comparisons among lesions were then made. Results: SUVavg and SUVmax are significantly higher for central nervous system (CNS) lymphoma than for other tumors (P < 0.01). High-grade gliomas showed significantly higher SUVavg and SUVmax than the low grade gliomas (P < 0.05) and metastatic tumor showed higher SUVavg and SUVmax than all gliomas, both low and high grade (P < 0.05). When the lowest values of CNS lymphoma parameter were used as cutoff levels to distinguish CNS lymphomas from other tumors (i.e. 100% sensitivity), SUVmax was the most accurate parameter. Using a SUVmax of 15.0 as a cutoff for diagnosing CNS lymphoma, only one case of metastasis (SUV max , 16.3) was found to be false positive in this study. Conclusion: FDG PET appears to provide additional information for differentiating common enhancing malignant brain tumors, namely lymphoma versus high grade glioma and metastatic tumor, particularly when differential diagnoses are difficult to narrow using MRI alone.