We report a case of myelodysplastic syndrome (MDS) with unique histopathological findings in which numerous infiltrated neutrophils exhibited nuclear segmentation anomalies. In comparison with well-described neutrophilic dermatoses of myelodysplastic syndrome such as Sweets syndrome and pyoderma gangrenosum, this case took a rapid and aggressive clinical course. We suggest that a nuclear segmentation anomaly, pseudo Pelger-Hiiet anomaly, is likely to reflect acute transformation of MDS and can be a poor prognostic marker.