Targeted use of fluorescence in situ hybridization (FISH) in cytospin preparations

Abstract

Fluorescence in situ hybridization (FISH) results from fine needle aspirates (FNA) of B-cell non-Hodgkin lymphomas (NHLs) were reviewed to 1) investigate the value added by using specific gene rearrangement probes to lymphoma diagnosis, prognosis, and subtyping; and 2) evaluate the prevalence of cytogenetic alterations other than specific translocations. FISH results from assays performed on cytospin preparations from NHL FNAs over a 6-year period (2003-2009) were selected. Immunophenotyping, clinical data, and cytomorphologic data were reviewed according to the current World Health Organization (WHO) classification system. Hybridized probes, the purpose for the assay (subtyping or prognosis), and the cytogenetic abnormalities observed were retrieved from cytology reports. Data was categorized according to specific rearrangements and other chromosomal abnormalities. Successful results were obtained in 284 (95.3%) of 298 cases from 282 patients. Abnormalities were found in 216 (76%) cases and 68 (24%) did not show alteration. Among cases submitted for subtyping, 198 showed FISH-positive results, and specific gene rearrangements were found in 122 (61.6%) cases as follows: follicular 82, mantle cell 21, marginal zone 3, "dual hit" 13, and Burkitt lymphoma 3. In 21 cases, abnormalities were useful for prognosis. Nonspecific alterations alone or in combination with translocations were found in 98 cases. FISH performed on cytospin preparations was useful for confirmation of specific subclasses of NHL and may also provide valuable prognostic information. Cytogenetic abnormalities other than specific translocations were frequently found and could provide supportive evidence for a definitive diagnosis of lymphoma in FNA.