Transient neutrophil morphological abnormalities in a post-chemotherapy patient receiving G-CSF

A 59-year-old male patient with gastric adenocarcinoma and peritoneal metastasis was admitted for periodic treatment with “sintilimab plus albumin-bound paclitaxel.” Prior to admission, the patient had undergone three treatment cycles. On the day before admission, he received an outpatient injection of albumin-bound paclitaxel. On the afternoon of admission, pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) was administered. The subsequent complete blood count (CBC) showed WBC 2.28 × 10⁹/L, neutrophil 1.82 × 10⁹/L, RBC 98 × 10¹²/L, and platelets 183 × 10⁹/L the following morning. The scattergram analysis from Sysmex XN-9000 indicated an abnormality, triggering the need for peripheral blood smear review. The sample slide was automatically prepared and stained using SP-10 (Sysmex) and analyzed by Sysmex DI-60, an automated cell-locating image analysis system. Neutrophils in the peripheral blood smear exhibited the following abnormalities (Figure 1): nuclear hyposegmentation; nuclear hypersegmentation (8–9 lobes); abnormal nuclear segmentation especially detached nuclear fragment; marked cytoplasmic hypergranularity and toxic granulation; pseudo-Pelger-Huët anomaly; clumped chromatin and asynchronous nuclear-to-cytoplasmic maturation. Additionally, giant platelets and monocyte vacuolization could be observed.

Although individual cases have reported some of the changes above, it is rare for all these abnormalities to occur simultaneously in a single patient sample. The peripheral blood film with macropolycytes and “giant” monocytes had been reported before.¹ However, “giant” monocytes were not observed in the peripheral blood of this patient. In the description of the various morphological abnormalities observed in Figure 1, it is noteworthy that detached nuclear fragments were present (Figure 1J,N), which is a characteristic feature of neutrophil dysplasia induced by G-CSF.² It is also noteworthy that the scattergram analysis of the patient's previous treatment cycles did not show significant abnormalities. On the fourth day of hospitalization, his CBC revealed the following results: WBC 0.93 × 10⁹/L, neutrophil 0.49 × 10¹²/L, RBC 87 × 10¹²/L, and platelets 117 × 10⁹/L. Importantly, this time the slide showed the absence of abnormal neutrophils except for neutrophil vacuolation and the presence of macropolycytes. In this patient, PEG-rhG-CSF may be responsible for the peripheral blood film findings that mimic MDS characteristics, including Pelger-like cells, detached nuclear fragment, abnormal nuclear shape and clumped chromatin.³

The authors declare no conflicts of interest.