Leukaemic blast cannibalism in acute megakaryoblastic leukaemia with myeloid sarcoma

• DOI: 10.1111/bjh.14002
• Publication Date: 2016-03-31T05:06:58Z
• Authors: Rosario M. Morale...; Teresa Caballero‐...; Teresa Knight; Alejandro García; Ricardo Bernal; Juan J. Borrero
• Keywords: Male; Infant; Magnetic Resonance Imaging; Ilium; Radiography; 03 medical and health sciences; Fatal Outcome; 0302 clinical medicine; Cytophagocytosis; Leukemia, Megakaryoblastic, Acute; Humans; Sarcoma, Myeloid

A 12-month-old infant was admitted to hospital after his parents had noticed a painless tumour involving left hip over the previous 3 weeks. Examination showed hard mass with indistinct borders and no inflammatory signs. Neither lymphadenopathy nor hepatosplenomegaly detected. full blood count only thrombocytosis, platelet 600 × 109/l. No blast cells or leucoerythroblastic features were seen in film. Other tests unremarkable. Imaging studies plain radiography magnetic resonance imaging 47 58 53 mm osteolytic lesion centred on iliac bone, infiltrating displacing iliopsoas muscles adjacent gluteal region (left). An biopsy consisting of discohesive small medium-sized round nuclei, which manifested diffuse pattern infiltration. Images cannibalism among could be observed (bottom right). Immunohistochemical revealed positivity for CD34, CD31 CD42b. other markers, including markers cell tumours, observed. bone marrow aspirate hypercellular 55% cells. The blasts irregular nuclei numerous nuclear protrusions occasionally they occurred clusters. engulfing (top 76% acid phosphatase (myeloperoxidase alpha-naphthyl-acetate-esterase negative). Flow cytometry identified an immature population (CD34+CD117+CD45−) expressing glycoproteins (cytoplasmic CD61 CD41+, surface membrane CD41−/weak, CD42a+ CD42b+), myeloid-associated marker. lineage-specific HLA-DR negative. karyotype normal. Fluorescence situ hybridization did not demonstrate BCR-ABL1 rearrangement KMT2A (MLL) EWSR1. mutation detected FLT3 NPM1. Bone adequate global haematopoiesis. Anti-CD34 demonstrated pathological accumulations small, scattered diagnosis acute megakaryoblastic leukaemia associated myeloid sarcoma made. Treatment consisted cytarabine, idarubicin etoposide addition intrathecal chemotherapy. patient died due pulmonary haemorrhage day 17 post-chemotherapy. Cellular is form phagocytosis internalization another same lineage. It has been linked higher metastatic potential poorer prognosis non-haematological tumours. Cannibalism rare leukaemias.