Revised: 10 November 2018

Accepted: 20 November 2018

DOI: 10.1002/jimd.12020

IMAGES IN METABOLIC MEDICINE

Focal cerebellar infarction as an initial sign of mitochondrial
myopathy, encephalopathy, lactic acidosis, and stroke-like
episodes
Ara Ko1,2 | Sang-Jun Lee3 | Young-Mock Lee3
1

Department of Pediatrics, Pusan National
University Children's Hospital, Pusan
National University School of Medicine,
Yangsan, Republic of Korea

Abstract
Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes
(MELAS) is a type of mitochondrial disorder and stroke-like lesions are observed

2

Research Institute for Convergence of
Biomedical Science and Technology, Pusan
National University Yangsan Hospital,
Yangsan, Republic of Korea
3

Department of Pediatrics, Gangnam
Severance Hospital, Yonsei University
College of Medicine, Seoul, Republic of
Korea

prominently in the brain magnetic resonance imaging. Those stroke-like lesions of
MELAS patients are usually located in the posterior quadrants and do not correspond to typical vascular territories. This case illustrates that focal cerebellar infarction can be the sole initial sign of MELAS.
KEYWORDS
ataxia, cerebellum, dysarthria, MELAS, mitochondria

Correspondence
Young-Mock Lee, Department of Pediatrics,
Gangnam Severance Hospital, Yonsei
University College of Medicine, 2011
Eonju-ro, Gangnam-gu, Seoul 06273,
Republic of Korea.
Email: [email-masked]

Mitochondrial myopathy, encephalopathy, lactic acidosis,
and stroke-like episodes (MELAS) is a type of mitochondrial
disorder often presented with symptoms such as seizures,
headaches, diabetes mellitus, muscle weakness, sensorineural
hearing loss, myopathy, and sudden neurological deficits.1
Among several mutations known to be associated with
MELAS, the m.3243A>G mutation in the mitochondrial
transfer RNA Leu(UUR) gene is one of the most common type.
Stroke-like lesions are observed prominently in the brain
magnetic resonance imaging (MRI) of MELAS patients.2
A 5-year-old boy with no previous medical history presented with dysarthria and mild right-sided ataxia. A focal
infarction in the right posterior cerebellum was noted in the
brain MRI (Figure 1). His plasma lactate level (7.2 mmol/L)
indicated lactic acidosis. Evaluation workup for the

mitochondrial disease was conducted and m.3243A>G
mutation was identified. After time, dysarthria and ataxia
improved but he did not completely recover. Focal seizures
and stroke-like episodes developed 3 years after while dysarthria and ataxia persisted. The second brain MRI revealed
new cortical stroke-like lesions and a cerebellar lesion
(Figure 2).
This is the first report describing focal cerebellar infarction as a presenting sign of MELAS. The patient of this case
showed dysarthria and ataxia with focal cerebellar infarction
shown on MRI. The cerebellar lesion on MRI was very
small considering his symptoms, but together with clinical
circumstances we concluded that this is the responsible
lesion for dysarthria and ataxia of the patient. One possible
explanation is that actual cerebellar involvement is larger
than the lesion grossly manifested on MRI. Those stroke-like
lesions of MELAS patients are usually located in the

Ara Ko and Sang-Jun Lee contributed equally to this study.

J Inherit Metab Dis. 2019;1–2.

wileyonlinelibrary.com/journal/jimd

© 2018 SSIEM

1

KO ET AL.

2

posterior quadrants and do not correspond to typical vascular
territories.1 However, there are some patients with mitochondrial encephalopathies associated with the m.3243A>G
mutations who have deep gray matter changes on MRI without stroke-like lesions.2 Also, there are various reported cases
showing cerebellar involvement in MELAS patients concomitantly with other cortical involvement or appearing during disease course.3–5 This case further illustrates that focal
cerebellar infarction can be the sole initial sign of MELAS.
All procedures performed in studies involving human
participant were in accordance with the ethical standards of
the institutional and national research committee. Informed
consent was obtained from the patient included in the study.
CONF LICT S O F I N TER EST
None

FIGURE 1

Initial brain MRI. A, B, Normal cerebral appearance
on T2 images. C, D, Diffusion restriction focus in the right
cerebellum on diffusion-weighted images suggesting acute infarction
(arrow)

Ethical approval: All procedures performed in studies
involving human participant were in accordance with the
ethical standards of the institutional and national research
committee.
Informed consent: Informed consent was obtained from the
patient included in the study.
OR CI D
Young-Mock Lee

https://orcid.org/0000-0002-5838-249X

REF ER ENC ES
1. Ito H, Mori K, Kagami S. Neuroimaging of stroke-like episodes in
MELAS. Brain Dev. 2011;33(4):283-288.
2. Tschampa HJ, Urbach H, Greschus S, Kunz WS, Kornblum C. Neuroimaging characteristics in mitochondrial encephalopathies associated with the m.3243A>G MTTL1 mutation. J Neurol. 2013;
260(4):1071-1080.
3. Nakamura S, Yoshinari M, Wakisaka M, et al. Ketoacidosis accompanied by epileptic seizures in a patient with diabetes mellitus and
mitochondrial myopathy, encephalopathy, lactic acidosis and strokelike episodes (MELAS). Diabetes Metab. 2000;26(5):407-410.
4. Ng YS, Lax NZ, Maddison P, et al. MT-ND5 mutation exhibits
highly variable neurological manifestations at low mutant load.
EBioMedicine. 2018;30:86-93.
5. Taieb G, Juntas-Morales R, Renard D. Progression of stroke-like
lesions along the cortico-ponto-cerebellar tract. Acta Neurol Belg.
2017;117(1):309-310.

FIGURE 2

Follow-up brain MRI. A, B, Multiple scattered foci
of cortical hyperintensities at both temporal, parietal, and occipital
lobes on T2 images, suggesting multifocal cortical infarctions
(arrows). C, Subtle diffusion restriction foci at right cerebellar
hemispheric inferior portion on diffusion-weighted images
(arrows). D, Increased signal lesion in fluid-attenuated inversionrecovery images of the right inferior cerebellum (arrow)

How to cite this article: Ko A, Lee S-J, Lee Y-M.
Focal cerebellar infarction as an initial sign of
mitochondrial myopathy, encephalopathy, lactic
acidosis, and stroke-like episodes. J Inherit Metab
Dis. 2019;1–2. https://doi.org/10.1002/jimd.12020