2021 年 3 巻 8 号 p. 474-475
An 82-year-old man was admitted to Nihon University Itabashi Hospital due to congestive heart failure. He had a history of pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation and permanent pacemaker implantation for atrioventricular block 2 and 7 years ago, respectively. The patient died of ischemic colitis 59 days after being hospitalized, and an autopsy was performed.
Gross examination revealed biventricular hypertrophy with a tan and rubbery myocardium in the short-axis sections (Figure A). Coarse endocardium of the left atrium and PVI scars were identified (Figure B). Systemic transthyretin-related amyloidosis in the heart, lung, liver, spleen, digestive tract, kidney, thyroid gland, and urinary bladder was confirmed by Direct Fast Scarlet (Figure C,D) and immunohistochemistry (Figure E). The PVI scar exhibited osseous metaplasia with bone marrow formation (Figure F,G), adjacent to amyloid deposition (Figure F–I).
(A) Transverse sections of the heart. (B) Endocardium of the left atrium. Arrows indicate amyloid deposition and arrowheads indicate the pulmonary vein isolation (PVI) scar. Scale bar, 1 cm. (C–E) Transthyretin-related amyloid deposition in the septum of left ventricle: hematoxylin-eosin (HE) staining (C); Direct Fast Scarlet staining (D); and ATTR immunohistochemistry (E). (F–I) PVI scar exhibiting osseous metaplasia (arrows; HE [F] and Direct Fast Scarlet [G] staining) adjacent to the amyloid deposition (arrowheads). (H,I) Higher-magnification images of the boxes in (F) and (G), respectively.
The presence of osseous metaplasia has been reported in patients with amyloidosis in organs other than the heart, such as lung, breast and tongue.1–3 However, such metaplasia has not been reported previously in PVI scars. This report demonstrates a rare case of metaplastic change in the PVI scar in a patient with systemic amyloidosis.
The authors have no conflicts of interest to declare.
