BackgroundMore than 50% of patients with myelodysplastic syndromes present cytogenetic aberrations at diagnosis. Partial or complete deletion of the long arm of chromosome 5 is the most frequent abnormality. The aim of this study was to apply fluorescence in situ hybridization of 5q31 in patients diagnosed with de novo myelodysplastic syndromes in whom conventional banding cytogenetics study had shown a normal karyotype, absence of metaphases or an abnormal karyotype without evidence of del(5q). Design and MethodsWe performed fluorescence in situ hybridization of 5q31 in 716 patients, divided into two groups: group A patients (n=637) in whom the 5q deletion had not been detected at diagnosis by conventional banding cytogenetics and group B patients (n=79), in whom cytogenetic analysis had revealed the 5q deletion (positive control group). ResultsIn group A (n=637), the 5q deletion was detected by fluorescence in situ hybridization in 38 cases (5.96%). The majority of positive cases were diagnosed as having the 5q-syndrome. The deletion was mainly observed in cases in which the cytogenetics study had shown no metaphases or an aberrant karyotype with chromosome 5 involved. In group B (n=79), the 5q deletion had been observed by cytogenetics and was confirmed to be present in all cases by fluorescence in situ hybridization of 5q31. ConclusionsFluorescence in situ hybridization of 5q31 detected the 5q deletion in 6% of cases without clear evidence of del(5q) by conventional banding cytogenetics. We suggest that fluorescence in situ hybridization of 5q31 should be performed in cases of a suspected '5q-syndrome' and/or if the cytogenetic study shows no metaphases or an aberrant karyotype with chromosome 5 involved (no 5q-chromosome).

Purpose: To report a case of primary choroidal lymphoma that was confirmed by polymerase chain reaction–based clonality testing. Case report: A 50-year-old woman presented with unilateral progressive vision loss. Fundus examination and B-ultrasonography demonstrated diffuse choroidal thickening without vitritis. Pars plana vitrectomy and subretinal biopsy were performed, and histopathologic analysis revealed choroidal B-cell lymphoid hyperplasia without evidence of neoplasia. Extraocular extension was ruled out, and transitory improvement was observed with oral steroids. After 1-year follow-up, she was referred to our hospital and clonality testing was performed using the samples taken months before. First, we used a forensic DNA extraction kit, and then, a multiplex polymerase chain reaction was carried out using the IgH Rearrangements Molecular Analysis Kit. Clonal rearrangement was identified for the immunoglobulin heavy chain framework regions 1 and 2, and B-cell choroidal lymphoma was confirmed. The patient began treatment with intravitreal rituximab, but no response was observed. Finally, complete regression was achieved using external beam radiotherapy. Conclusion: Polymerase chain reaction–based clonality testing can be a valuable tool to confirm a choroidal lymphoproliferative process.