Diagnosing Mds; Do We Really Need to FISH?

Objectives

Making a definitive diagnosis of myelodysplastic syndrome (MDS) currently entails review of morphology on peripheral blood and bone marrow as well as cytogenetics by standard karyotyping. Fluorescence in situ hybridization (FISH) panel is performed to identify specific abnormalities in addition to karyotyping.

Methods

We reviewed 186 patients who had undergone bone marrow biopsy for suspected MDS from 2016 to 2018 across our health system and subsequently had karyotyping and FISH testing performed.

Results

We identified 186 patients in our study cohort, 164 of these patients had karyotype and FISH testing available. There was excellent concordance rate of 93% (152 of 164) between karyotype and FISH.

Among the 164 bone marrow biopsy samples reviewed, 40(24.4%) eventually had a confirmed diagnosis of MDS. Concordance rate of karyotyping and FISH results in the confirmed cases of MDS was 75% (30 of 40). Overall, 9 of the 40 cases (22.5%) had discordant findings, of these 20% (8 of 40) demonstrated abnormal karyotype analysis with normal FISH while only 1 of 40 (2.5%) had normal karyotype with abnormal FISH diagnostic of MDS. The abnormal FISH finding was a cryptic RUN X1 deletion.

Conclusion

Our study indicated excellent concordance between karyotype and MDS-FISH. FISH rarely added additional value to karyotype.