Hematopoiesis/Erythropoiesis in Myocardial Infarcts

Abstract

Extramedullary hematopoiesis occurring in the myocardium has previously only been reported in a single case of a neonate with cyanotic congenital heart disease. Herein we report the incidental discovery of extramedullary hematopoiesis or pure erythropoiesis in four failing adult hearts with myocardial infarction. In two cases, extramedullary hematopoiesis or erythropoiesis was identified in cardiectomy specimens removed at orthotopic heart transplantation; in two other cases, erythropoiesis was found in left ventricular tissue removed at the time of implantation of left ventricular assist devices. Myocardial hematopoiesis/ erythropoiesis was identified based on characteristic light-microscopic findings in routinely processed tissue and was confirmed by immunhistochemistry using monoclonal antibodies to the erythroid cell marker glycophorin A (positive in all cases), the megakaryocyte marker CD61, and the granulocyte marker neutrophil elastase (the latter two markers positive in one case only). None of the four patients had a myeloproliferative disorder or evidence of a myelophthisic process. No hematopoietic elements were identified in 109 cardiectomy specimens without acute or recent infarcts. Myocardial hematopoiesis or erythropoiesis could represent heretoforeunrecognized manifestations of altered cytokine expression in patients with heart failure due to myocardial infarction.

Extramedullary Hematopoiesis: A New Look at the Underlying Stem Cell Niche, Theories of Development, and Occurrence in Animals

“…In another report, EMH was found adjacent to zones of myocardial infarction in 4 patients, also without bone marrow disorders. 29 Immunohistochemistry for glycophorin A, myeloperoxidase, and factor VIII-related antigen was performed on selected cases to document cells of erythroid, myeloid, and megakaryocytic origin, respectively. 29,38 These findings suggest that healing infarcts provide both the architectural components (loose connective tissue with neovascularization) and the cellular components of a microenvironment conducive to hematopoietic cell homing and proliferation.…”

Extramedullary Hematopoiesis in Uterine Leiomyoma Associated with Numerous Intravascular Thrombi

“…The presence of EMH in the thrombi could be explained by the accumulation of circulating hematopoietic precursor cells that were released due to fast bone marrow turnover in the condition of severe chronic anemia. In addition, EMH was previously reported to be present in myocardial infarcts probably related to tissue response to injury [18]. Although EMH has been reported in endometrium, cervix, and uterine isthmus [19–21], our finding of EMH present in both smooth muscle and within the thrombi of uterine leiomyoma is unusual.…”

Mass-forming extramedullary hematopoiesis diagnosed by fine-needle aspiration cytology

“…25 Rarely, it occurs unassociated with a hematologic disorder and has been reported in unusual settings such as myocardial infarction. 26 Although EMH usually occurs in a milieu that supports the proliferation of primitive hematopoietic bone marrow elements like liver, spleen, and lymph node, it has been reported in many parts of the body including the thyroid, kidney, paravertebral soft tissue, extradural space, paranasal sinuses, intraocular choroid, uterine isthmus, adrenal glands, as well as in body cavity fluids. [2][3][4][5]9,11,20,[27][28][29][30][31][32][33] Historically, EMH was an autopsy diagnosis.…”