To the Editor,
Cardiac transplantation remains the gold standard therapy for advanced heart failure. The orthotopic technique is employed by virtually all transplant centres, in which the recipient's heart is removed and replaced by donor organ.
- John R.
- Liao K.
Orthotopic heart transplantation.
Oper Tech Thorac Cardiovasc Surg. 2010; 15: 138-146
2The contribution of pathology to the success of cardiac transplantation is well established.
- Kirklin J.K.
- Young J.B.
- McGiffin D.C.
The heart transplant operation.
in: Kirklin J.K. Young J.B. McGiffin D.C. Heart Transplantation. Churchill Livingstone, Philadelphia2002: 339
3Cardiac transplant recipients are routinely monitored for rejection by endomyocardial biopsies (EMB) of the right ventricle. EMB is typically performed under local anaesthesia by passing a bioptome through the right internal jugular vein across the tricuspid valve and into the right ventricle. Sampling is usually performed on the fluoroscopic guidance along the interventricular septum.
- Buja L.M.
- Butany J.
4th ed. Elsevier, 2016
- Tschöpe C.
- Kherad B.
- Schultheiss H.P.
How to perform an endomyocardial biopsy?.
Turk Kardiyol Dern Ars. 2015; 43 (572–5)
5The biopsy material usually includes endocardium and myocardium with endocardium representing endothelial lined tissue with underlying bundles of smooth muscle and connective tissue and myocardium representing myocytes, interstitium and small intramyocardial blood vessels.
- Cooper L.T.
- Baughman K.L.
- Feldman A.M.
- et al.
The role of endomyocardial biopsy in the management of cardiovascular disease: a scientific statement from the American Heart Association, the American College of Cardiology, and the European Society of Cardiology.
Circulation. 2007; 116: 2216-2233
6Repeated biopsy of the same area of the right ventricle gives rise to changes, which include haemorrhage, granulation tissue formation, scarring and an associated inflammatory response.
- Olsen E.G.L.
Atlas of cardiovascular pathology.
in: Gresham G.A. Current Histopathology. 1st ed. MTM Press Limited, Lancaster1987
7We describe a rare case of squamous metaplasia arising in the endothelium of an EMB resulting from repeated biopsy of the same site.
- Miller D.V.
- Revelo M.P.
Diagnostic Pathology Cardiovascular.
2nd ed. Elsevier, 2018
A 53-year-old female heart transplant recipient was biopsied for routine assessment of rejection. The histology revealed six portions of tissue representing endocardium and underlying myocardium (Fig. 1A). The endocardium appeared mildly thickened and somewhat hyalinised. The myocardium showed no evidence of necrosis or interstitial inflammation. The intramyocardial small blood vessels were identified within the myocardium and were histologically unremarkable. There was no significant interstitial fibrosis. However, one fragment showed lining endothelium expanding into a multilayered, transitional type epithelium with underlying subepithelial connective tissue containing small bundles of smooth muscle, confirming that this cellular proliferation was arising in the endothelium (Fig. 1B). Immunohistochemistry for epithelial lineage (AE1/3) squamous cell markers (CK5/6 and P40), mesothelial lineage (calretinin) and an endothelial marker (ERG) was carried out. In addition, a smooth muscle marker (SMA) and a muscle marker (myogenin) were carried out to identify the smooth muscle bundles in the subendocardial tissue. The cellular proliferation showed positive staining for AE1/3, CK5/6 and P40 stains (Fig. 2A–C) and no staining for calretinin and ERG, confirming squamous differentiation. The SMA highlighted the smooth muscle bundles in the subendocardium confirming the orientation of the tissue (Fig. 2D). The myogenin stain only highlighted the cardiac myocytes (Fig. 2E).
Metaplasia is a process whereby one type of mature tissue is replaced by another type of mature tissue not indigenous to that organ or tissue, which likely represents a reactive or reparative response to chronic injury or irritation.
8To the best of our knowledge, squamous metaplasia occurring in the endothelium in transplant biopsies has not previously been described and should not be mistaken for dysplasia or malignancy arising in the endocardium.
- Kumar V.
- Abbas A.K.
- Aster J.C.
Robbins and Cotran Pathologic Basis of Disease.
9th ed. Elsevier, 2015
Conflicts of interest and sources of funding
The authors state that there are no conflicts of interest to disclose.
- Orthotopic heart transplantation.Oper Tech Thorac Cardiovasc Surg. 2010; 15: 138-146
- The heart transplant operation.in: Kirklin J.K. Young J.B. McGiffin D.C. Heart Transplantation. Churchill Livingstone, Philadelphia2002: 339
- Cardiovascular Pathology.4th ed. Elsevier, 2016 (Chapter 17, Pathology of cardiac transplantation)
- How to perform an endomyocardial biopsy?.Turk Kardiyol Dern Ars. 2015; 43 (572–5)
- The role of endomyocardial biopsy in the management of cardiovascular disease: a scientific statement from the American Heart Association, the American College of Cardiology, and the European Society of Cardiology.Circulation. 2007; 116: 2216-2233
- Atlas of cardiovascular pathology.in: Gresham G.A. Current Histopathology. 1st ed. MTM Press Limited, Lancaster1987 (Chapter 1, The normal heart)
- Diagnostic Pathology Cardiovascular.2nd ed. Elsevier, 2018 (Chapter 1, Heart, endomyocardial biopsy)
- Robbins and Cotran Pathologic Basis of Disease.9th ed. Elsevier, 2015 (Chapter 7, Neoplasia)
Published online: November 16, 2022
Publication stageIn Press Corrected Proof
© 2022 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.