Journal of Hematopathology | 2021
Coexistence of pseudo-Pelger-Hüet anomaly and faggot cells in acute promyelocytic leukemia during chemotherapy
Abstract
Pelger-Huët anomaly (PHA) is an autosomal dominant hematological trait, characterized by neutrophil nuclear hypolobulation and excessively abnormal aggregation of chromatin, classically described as “pince-nez” appearance or peanut-shaped [1]. Pseudo-Pelger-Hüet anomaly, as the name implies, the neutrophil dysplasia similar to PHA, but is not an inherited condition. It could be present in bacterial or viral infections, under the effect of some drugs, such as immunosuppressors, ibuprofen, and sulfonamide, as well as in certain disease states, including angina, Addison’s disease, rheumatoid arthritis, acute leukemia, and myelodysplastic syndrome. It is also known as acquired Pelger-Huët anomaly, and occasionally, eosinophils are also hyposegmented with coarsely clumped chromatin [2]. Herein, we report a young man diagnosed as acute promyelocytic leukemia (APL) with PML-RARA , with an occurrence of pseudoPelger-Huët anomaly related to chemotherapy. A 28-year-old male patient was diagnosed with APL with PML-RARA for 21 days. At the initial diagnosis, his full blood counts showed pancytopenia with hemoglobin concentration 91 g/L, total white blood cell (WBC) count 2.83 × 109/L (abnormal promyelocytes 25%, normal mature neutrophils 54%, lymphocytes 20%, and monocytes 1%), absolute neutrophil count 0.8 × 109/L, and very low platelet count 22 × 109/L. Abnormal scatter diagram with no boundary between cells in the scatter plot was observed by automatic blood cell analyzer (black arrow in Fig. 1A). Peripheral blood films revealed large numbers of abnormal promyelocytes, with kidney-shaped or bilobed nuclei and abundant cytoplasm containing large and numerous azurophilic granules, which entirely obscure the nuclear-cytoplasmic margin (Fig. 1B–D); in the meantime, plenty of faggot cells, named for the resemblance of multiple Auer rods to a bundle of sticks, were observed (Fig. 1B–C), raising an initial suspicion of the hypergranular APL. In addition, a normal mature neutrophil was also present on the smear (Fig. 1E). The morphological result of bone marrow examination was similar to the blood films. Reverse transcriptase polymerase chain reaction (RT-PCR) detected the PMLRARA rearrangement. All these findings supported the diagnosis of APL with PML-RARA . While this time, he underwent a blood routine examination followed by one cycle of chemotherapy with all-retinoic acid (ATRA) plus arsenic trioxide (ATO). Laboratory findings showed white blood cell count 1.66 × 109/L, neutrophil count 0.74 × 109/L, the red blood cell count 2.35 × 1012/L, hemoglobin of 76 g/L, and platelet 37 × 109/L. The WBC scatter plot suggested decreasing abnormal cells compared with the initial diagnosis (black arrow in Fig. 1F). A peripheral blood smear showed a large number of mature-appearing neutrophils, characterized by nuclear hyposegmentation, excessively clumped chromatin, and a large amount of Auer rods consisted in cytoplasm (Fig. 1G–H). Meanwhile, many “pince-nez” appearance neutrophils were observed (Fig. 1I–J). Interestingly, one month after treatment, the pseudo-Pelger-Hüet anomaly appearance of neutrophils disappeared and was identical to the normal morphology prior chemotherapy. As is well known, Auer rods are pathognomonic cue of acute myeloid leukemia (AML) and myelodysplastic syndrome, usually present in immature hematopoietic progenitors. The presence of Auer rods in mature neutrophils is very uncommon. To date, very few cases has been described including CBFB-MYH11-positive and RUNX1-RUNX1T1positive AML [3, 4]. Coexistence of numerous Auer rods and typical pseudo-Pelger-Hüet anomaly in mature neutrophils was extremely unusual. These pictures provide a * Xueyan Chen [email protected]