Aplastic Anemia and Monosomy 7-Associated Dysmegakaryocytopoiesis

Michelle M. Dolan, MD; Timothy P. Singleton, MD; Joseph Neglia, MD, MPH; Adina Cioc, MD

Disclosures

Am J Clin Pathol. 2006;126(6):925-930. 

In This Article

Abstract and Introduction

Abstract

Aplastic anemia (AA) is marrow failure due to an inadequate number of hematopoietic cells in the marrow. Prior reports have described a more aggressive clinical course in aplastic anemia with monosomy 7.

We report 3 pediatric cases of AA with normal cytogenetics followed by acquisition of monosomy 7. Bone marrow biopsies were initially diagnostic of AA but later showed monosomy 7 and an increased number of megakaryocytes with small hypolobated nuclei. Immunohistochemical stains for CD61 highlighted the marked dysmegakaryocytopoiesis. The marrow blast percentage was increased in only 1 patient with 4.6% blasts. The 3 patients underwent bone marrow transplantation, and each has remained disease free for 7 to 18 months after transplantation.

Pediatric patients with AA and normal cytogenetics may develop monosomy 7 with a myelodysplastic syndrome, unclassified. Patients with AA and monosomy 7 should be evaluated for dysmegakaryocytopoiesis.

Introduction

Aplastic anemia (AA) is a bone marrow failure syndrome that is believed to be due to immunologic destruction of otherwise normal hematopoietic cells.[1] Outcome depends on the etiology and treatment, which may include antithymocyte globulin (ATG), cyclosporine, other immunosuppressive regimens, and bone marrow transplantation (BMT). In a subset of patients, myelodysplastic syndromes (MDSs) or acute leukemias may develop.[2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17] The most frequently reported cytogenetic abnormality in these cases is monosomy 7.[2,3,4,5,6,7,8,9,10,11,13,14] Reports have described a more aggressive clinical course in AA with monosomy 7, a cytogenetic abnormality associated with MDS.

We describe 3 pediatric patients with AA in whom monosomy 7 developed during the course of their disease. These patients received similar therapeutic regimens, including ATG, steroids, and cyclosporine. Two boys, ages 9 and 12 years, were previously healthy. A 17-year-old girl had a history of chronic active hepatitis. Bone marrow biopsies were initially diagnostic of AA and later showed monosomy 7 and myelodysplasia characterized by an increased number of small hypolobated megakaryocytes, highlighted with immunohistochemical stains for CD61. Within weeks to months of the development of monosomy 7, the 3 patients underwent BMT, and each has remained disease free for 7 to 18 months after transplantation.

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