Increased incidence of leukemia in Down’s syndrome is a well established fact. An interesting entity known as transient myeloproliferative disorder (TMPD) has been rarely described to occur in Down’s syndrome which usually does not warrant treatment(1,2). We report a child of Down’s syndrome with TMPD.

A 20-day-old baby girl presented with history of icterus since birth, abdominal distension and decreased feeding for 15 days. The baby had features typical of Down’s syndrome. Liver was 5 cm below costal margin and spleen was enlarged (2 cm). Peripheral smear showed normochromasia with anisocytosis, macrocytosis, polychromasia, nucleated RBC’s (3-4/HPF), few micro-megakaryocytes, myelocytes-4%, pro-myelocytes-2%, and blasts-38%. Blasts were myeloperoxidase and neuron specific enolase negative and had azurophillic cytoplasm with high nucleocytoplasmic ratio. Few blasts also had prominent nucleoli and azurophillic granules in the cytoplasm. Blasts had phenotype similar to megakaryocytic lineage of FAB7. Flow cytometry showed that these were CD34+, CD33+, HLADR+, CD38+, CD17+, CD13-, CD14-, CD2- and CD95-. Bone marrow showed only 4% blasts in contrast to 38% blasts in peripheral blood. A diagnosis of Down’s syndrome with TMPD was made. The child was followed up without any specific treatment. On follow up after 8 weeks, her total count decreased to 6,800 and blasts in peripheral blood were only 3%. HIDA scan was normal. Serum bilirubin decreased to 2.2 mg/dl. This baby expired at the age of three and half months due to septicemia.

TMPD can be differentiated from true leukemia by the following characters: (i ) In TMPD, the growth of blast cells regresses spontaneously within several weeks or months after birth without antileukemia therapy and permanent recovery is achieved, although relapses occur on rare occasions; (ii ) The ratio of blasts in bone marrow is low as compared with that in peripheral blood; (iii ) Extramedullary hematopoises of all three cell lineages can be demonstrated in peripheral hematopoietic tissues; (iv) The blasts have 21 trisomy with no other clonal chromosomal abnormalities; (v ) In vitro, the stem cell cultures show normal growth in colonies maturing into granulocytes; and (vi ) The proliferating blast cells show phenotypes of megakaryocytic lineage resembling FAB M7 (AMKL, acute megakaryoblastic leuke-mia)(1,3). Myelofibrosis is significantly absent in these cases though it is frequent in AMKL.

The controversial issue at present is treatment of this disorder. Rizzari et al. treated a terminally ill patient with prednisolone (40 mg/kg), allopurinol, duanorubicin (45 mg/m2 IV; one dose) and cytarabine (ARA-c) 300 mg/m2/day continuous infusion for 3 days and repeated after one month. This child was thriving well at 9 years of age. A trial of therapy might be indicated in cases who are terminally ill(3).

Neeta Jindal,
Nandita Ghoshal,
S.K. Kabra,
Department of Pediatrics,
All India Institute of Medical Sciences,
New Delhi 110 029, India.

1. Zubizarreta P, Sackmann Muriel F, Fernandez Barbieri MA. Transient myeloproliferative disorder associated with trisomy 21: Report of 2 cases with trisomy 21 mosaicism. Med Pediatr Oncol 1995; 25: 60-64.

2. Homans AC, Verssimo AM, Valcha V. Transient abnormal myelopoiesis of infancy associated with trisomy 21. Am J Pediatr Hematol Oncol 1993; 15: 392-399.

3. Rizzari C, Malberti R, Dell’Orto M, Milani M. Transient myeloproliferative disorder associated with trisomy 21: Is a short course of chemotherapy indicated in patients with liver impairment and severe clinical problems? Med Pediatr Oncol 1999; 32: 453-454.