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A 58-year-old male had presented with a non-healing ulcer, and incidentally was discovered to have leucocytosis along with anemia and thrombocytopenia. The complete hemogram was as follows: hemoglobin: 8.5g/dl, total leucocyte count: 35,300/dl, and platelets: 10,000/dl. On examination, there was no lymphadenopathy or organomegaly.

The photomicrographs of the Leishman Giemsa stained bone marrow aspirate smears (100X), depict a myeloid left shift; neutrophilic hypolobation; 'abnormal chromatin clumping’ in the nucleus of immature myeloid precursors, such as promyelocytes, myelocytes and metamyelocytes; and cytoplasmic hypogranularity. Dyserythropoeitic erythroid precursors and reduced platelets are also noted.

Atypical Chronic Myeloid Leukemia (aCML) is a subtype of MDS/MPN. Morphologically, in addition to the leucocytosis with a marked neutrophilia, aCML is characterised by dysgranulopoeisis and a lack of basophilia.(1)  The 'Syndrome of abnormal chromatin clumping’ is considered as a variant of aCML.(2) 

References:

1.       Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J, Arber DA, Hasserjian RP, Le Beau MM, Orazi A, Siebert R (Eds): WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th Edition). IARC: Lyon 2017.

2.       Orazi A, Germing U. The myelodysplastic/myeloproliferative neoplasms: myeloproliferative diseases with dysplastic features. Leukemia. 2008; 22: 1308–1319. doi: 10.1038/leu.2008.119.