A 71-year-old woman diagnosed with chronic myeloid leukaemia in blast crisis which associates features of dyserythropoiesis in the bone marrow smear. 

Peripheral blood smear showed a haemoglobin of 8.6 g/dL, leukocytes 98x109/L and 268 x109 platelets/L. Cytogenetic testing showed t(9;22)(q34;q11.2) [11] and monosomy 7 in Ph positive cells  

Red blood cells precursors show Howell-Jolly body-like inclusions presented as small, dense basophilic inclusions in the cytoplasm. The nuclear nature of the inclusions was demonstrated by fluorescence studies. 

Monosomy 7 is one of the chromosomal alterations most frequently associated with MDS, and its presence in bone marrow cells can generate significant consequences on the prognosis of other haematological pathologies. 

Although its association with CML is not established, series of clinical cases have been published that may suggest that there is an association with poor outcomes (1-2). 

1- Clark RE, Apperley JF, Copland M, Cicconi S. Additional chromosomal abnormalities at chronic myeloid leukemia diagnosis predict an increased risk of progression. Blood Adv. 2021 Feb 23;5(4):1102-1109. doi: 10.1182/bloodadvances.2020003570. PMID: 33616651; PMCID: PMC7903225. 

2- Karimata K, Masuko M, Ushiki T, Kozakai T, Shibasaki Y, Yano T, Abe T, Moriyama M, Toba K, Furukawa T, Aizawa Y. Myelodysplastic syndrome with Ph negative monosomy 7 chromosome following transient bone marrow dysplasia during imatinib treatment for chronic myeloid leukemia. Intern Med. 2011;50(5):481-5. doi: 10.2169/internalmedicine.50.4481. Epub 2011 Mar 1. PMID: 21372464.