OFP-05-006 Focus on the follicular variant of papillary thyroid carcinoma: Combination of the immunohistochemical markers CK19, HBME1 and TPO is associated with histopathological diagnosis, better than molecular markers Objective: The follicular variant (FVPTC) is the major variant of papillary thyroid carcinoma (PTC), ranging from 9 % to 22 % of all PTC. It remains however a problematic entity. Some consider that the encapsulated FVPTC (enFVPTC) have an excellent prognosis like follicular adenomas (FA); others showed that enFVPTCs had potential for hematogenous spread like follicular carcinoma. Its place in the spectrum the multivariate Cox regression the FLT3-ITD mutation (p= 0.001) was an independent poor prognostic factor, whereas the goodness-of-fit of the Minkowski fractal dimension an independent favorable prognosticator (p=0.025). The karyotype had no influence on survival. Conclusion: FLT3-ITD and chromatin fractal characteristics were more important as prognostic factors for overall survival than karyotype and gene methylation status. Financial Support: FAPESP and CNPq. Objective: The prevalence of Cyclin D1 (CyD1) positive Bcells with mantle cell lymphoma (MCL) phenotype in the mantle zones of reactive lymph nodes ("in situ" MCL/MCLIS). and related minimal MCL infiltrates in reactive lymphoid tissues of healthy individuals and in MCL patients are unknown. Method: All 1.292 reactive lymph nodes from unselected consecutive surgical specimens of 131 patients without a history of lymphoma obtained over a 3 months´period were stained for CyD1. Additionally, all morphologically reactive lymph nodes and extranodal lymphoid infiltrates of MCL patients from 2000 to 2011 were studied. Samples predating the lymphoma diagnosis for at least 2 months were available from 37/423 (8.7 %) patients. Results: A MCLIS was not identified. However, in four MCL patients, an early manifestation of MCL with mantle zone growth pattern was detected retrospectively, antedating the lymphoma diagnosis for 3-86 months. In six MCL patients, only small groups of CyD1 positive cells in morphologically reactive extranodal infiltrates were detected more than 2 months before the diagnosis of MCL (range 3-59 months). Conclusion: MCL "in situ" is an extremely rare phenomenon in morphologically reactive lymph nodes. In MCL patients, however, immunohistochemically detectable infiltrates of MCL cells antedating the lymphoma diagnosis were found in a significant proportion of cases (10/37=27 %).