Leukemia or leukemoid, Down syndrome or not?

Case Report Baby WM was the first live born child of the family. Her 18-year-old mother had swollen ankles, lower abdominal pain and reduced fetal movements at 31st weeks of gestation. Ultrasound scan showed fetal car-diomegaly and early hydropic changes including hepatomegaly and swollen placenta. No maternal-fetal haemorrhage could be demonstrated by Kleihauer test. A baby girl was delivered one week later by Caesarian section. Her birth weight was 1830 grams. Apgar scores were nine at first minute and ten at fifth minute. She was phenotypically normal. She had moderate pallor but no lymphadenopathy. There were no blue-moffin rashes. A grade 2/6 ejection systolic murmur was heard over the left sternal border and of characters in keeping with flow murmur. Her abdomen was distended and the liver edge was felt at 6 cm below the costal margin. The spleen was palpable at 4 cm below the costal margin She had respiratory distress that necessitated nasal CPAP support. CXR showed cardiomegaly with streaky lung fields. There was no pleural effusion. Echocardiogram showed a structurally normal heart except a small patent ductus arteriosus. There was no pericardial effusion. Blood count showed high white cell count at 73×10 9 /L, with blast cell predominance (47×10 9 /L). The haemoglo-bin was 9.7 g/dL and platelet count was 135×10 9 /L. Smear found the blast cells were morphologically undif-ferentiated. Circulating nucleated red cells showed features of dyserythropoiesis. The blast cells were negative for myeloperoxidase and Sudan black B on cytochemical staining. Immunophenotyping of the blast cells showed expression of megakaryocytic markers CD42b and CD61, as well as CD7. A panel of myeloid, B-cell and other T-cell lineage markers were negative. Cytogenetic study of her peripheral blood detected 47,XX,+21[16] on overnight culture and a mosaic pattern of 47,XX,+21[4]/46,XX[14] on PHA-stimulated culture. She had severe unconjugated hyperbilirubinaemia and successfully controlled by a double volume exchange transfusion performed at 32 hours of life. The clinical course was further complicated by ileal perforation with pneumoperitonium on day 3 of life. Ileostomy was performed. Histology showed focal inflammation and haemorrhage at perforation site with suspicious leukaemic infiltration. Liver biopsy performed during the operation showed mild to moderate polymorph infiltration at portal tracts and evidence of extramedullary haemopoesis, with focal collections of blast cells in sinusoidal areas. She was thought to be either a mosaic Down syndrome with transient abnormal myelopoiesis (TAM) or a normal baby with acquired +21 due to …