Transient abnormal myelopoiesis with extramedullary involvement in a down syndrome preemie leading to an unresponsive course despite chemotherapy

INTRODUCTION

Transient abnormal myelopoiesis (TAM) is a transient, clonal myeloproliferative disorder unique to Down Syndrome (DS) babies. It is characterized by increased peripheral blasts and presence of GATA1 mutation. The clinical spectrum ranges from jaundice and hepatosplenomegaly to multi-organ failure and death. Here we present a case of a premature baby with DS diagnosed to have TAM with extramedullary involvement at birth who had a fatal outcome.

CASE REPORT

A 30.3-week-old female fetus with DS had leukocytosis (WBC: 187.82 K/uL) with neutrophilia (ANC 27.65 K/uL), macrocytic anemia (RBC: 2.41 m/uL, Hb 8.8 g/dL, MCV 108.3, MCH 36.5, MCHC 33.7) and thrombocytosis (platelet count 361 K/uL) at birth. Liver panels demonstrated normal bilirubin levels with elevated liver enzymes (AST = 239 U/L, ALT = 216 U/L).

RESULTS

Peripheral smear showed marked leukocytosis with increased blasts (70%), nucleated RBCs, giant platelets, and megakaryocytic elements. Flow cytometry demonstrated two populations of cells: 20% myeloblasts and 26% dim CD45 CD34- cells. GATA1 mutation was present. Based on these findings a diagnosis of TAM with extramedullary hematopoiesis was made. She received two cycles of cytarabine chemotherapy. Though her WBC levels reached a low of 18.93 K/uL, she developed multi-organ failure, eventually leading to death on day 45.

DISCUSSION

TAM is a transient condition resulting in disease resolution in around 80% of cases. Death is reported in 10% of cases. Risk factors associated with early death include prematurity, hyperleukocytosis, elevated bilirubin levels. Management of high-risk babies with chemotherapy is recommended to improve survival.

Clinical features of 35 Down syndrome patients with transient abnormal myelopoiesis at a single institution

Transient abnormal myelopoiesis (TAM) is a unique clonal myeloproliferation characterized by immature megakaryoblasts that occurs in 5-10% of neonates with Down syndrome (DS). Although TAM regresses spontaneously in most patients, approximately 20% of TAM cases result in early death, and approximately 20% of survivors develop acute megakaryoblastic leukemia (AMKL). We retrospectively reviewed records of 35 DS patients with TAM to determine the correlation between clinical characteristics and blast percentage. Thirteen of the 35 patients were classified as low blast percentage TAM (LBP-TAM), defined as TAM with a peak peripheral blast percentage ≤ 10%. Although no patient with LBP-TAM experienced systemic edema, disseminated intravascular coagulation, or early death, eight patients had elevated direct bilirubin levels (> 2 mg/dl) and one developed AMKL. All patients with LBP-TAM had serum markers of liver fibrosis that exceeded the normal limits, and two patients underwent liver biopsy to clarify the etiology of pathological jaundice. Taken together, our results suggest that patients with LBP-TAM may be at risk of liver fibrosis and liver failure, similarly to patients with classical TAM. Although these patients generally have a good prognosis, they should be carefully monitored for potential development of liver disease and leukemia.

Successful Liver Transplantation for Transient Abnormal Myelopoiesis-Associated Liver Failure

Infants with Down syndrome (DS) are at risk of developing a transient abnormal myelopoiesis (TAM). TAM occasionally involves liver fibrosis, which can be fatal. The management of liver disease in TAM has not yet been established and is mainly supportive. We report an infant with DS and TAM who developed end-stage liver failure. Liver dysfunction progressed even after blast cells disappeared from the circulation. He underwent a living-donor liver transplantation at 56 days of life without surgical complications. The explanted liver showed atrophy and severe fibrosis without leukemic cell infiltration. The posttransplant course was favorable with no hematological abnormality. He is doing well 8 months after transplantation. To the best of our knowledge, this report is the first showing that liver transplantation might be a treatment option for TAM-related liver failure.

Evolution of myeloid leukemia in children with Down syndrome

Children with Down syndrome (DS) have a markedly increased risk of leukemia. They are at particular risk of acute megakaryoblastic leukemia, known as myeloid leukemia associated with DS (ML-DS), the development of which is closely linked to a preceding temporary form of neonatal leukemia called transient abnormal myelopoiesis (TAM). Findings from recent clinical and laboratory studies suggest that constitutional trisomy 21 and GATA1 mutation(s) cause TAM, and that additional genetic alteration(s) including those in epigenetic regulators and signaling molecules are involved in the progression from TAM to ML-DS. Thus, this disease progression represents an important model of multi-step leukemogenesis. The present review focuses on the evolutionary process of TAM to ML-DS, and advances in the understanding of perturbed hematopoiesis in DS with respect to GATA1 mutation and recent findings, including cooperating genetic events, are discussed.

Transient leukemia in down syndrome: report of two cases with review of literature

Transient leukemia (TL) also referred to as transient abnormal myelopoiesis (TAM) or transient myeloproliferative disorder (TMD) is a unique syndrome that frequently occurs in newborns with Down syndrome (DS). It manifests in the first few days of life and shows leukocytosis with blast cells in the blood and bone marrow. This leukemia resolves spontaneously within first few months of life in the majority of cases. In this report we describe two newborns with a karyotype of 47,XY,+21, presented with marked leukocytosis and many blast cells in the peripheral blood. In both the cases, the blasts disappeared and the total leukocyte count reverted to normal without any specific treatment.