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Clinical History:
45 year-old female with history of systemic lupus
erythematosus treated with hydrochloroquine for years
but switched to chloroquine during the last year. She
presented with symptoms of volume overload and an
echocardiogram showed systolic dysfunction with low
ejection fraction. Her condition continue to worsen and
developed junctional bradycardia, pleuretic chest pain
and pulmonary congestion. Troponin levels were mildly
raised (1- 2 ng/ L; reference value
0.01 ng/mL or less). A myocardial biopsy was performed with
the diagnosis of chloroquine induced
cardiomyopathy.
Histology: H&E
staining in Figure A shows extensive cytoplasmic
vacuolization, along with areas of extensive myocyte
degeneration and severe disarray of myofibrils. There is
marked nuclear dysmorphism, and many nuclei are
small and hyperchromatic. PAS stain shows strong
cytoplasmic
staining (Figure B), which is removed after diastase
treatment (Figure C) confirming the presence of
glycogen within the myocytes. There is
no associated inflammatory process and trichrome staining shows
focal, mild interstitial fibrosis (Figure D). H&E
staining in Figure E is from a different case in
which myocyte vacuolation is present.
Electron Microscopy:
Electron microscopic examination reveals
cardiomyocytes with multiple large autophagosomes
and prominent sites of cytoplasmic degradation (Figures
F, G). Additionally, there is central replacement and
displacement of sarcomeres by marked accumulation of
secondary lysosomes including myeloid or curvilinear
(lamellar) bodies (Figure H). |
