Black toenail sign

Last revised by Rohit Sharma on 14 Jan 2023

Citation, DOI, disclosures and article data

Citation:

Sharma R, Black toenail sign. Reference article, Radiopaedia.org (Accessed on 24 Apr 2024) https://doi.org/10.53347/rID-160262

DOI:

https://doi.org/10.53347/rID-160262

Permalink:

https://radiopaedia.org/articles/160262

rID:

160262

Article created:

14 Jan 2023, Rohit Sharma ◉

Disclosures:

At the time the article was created Rohit Sharma had no financial relationships to ineligible companies to disclose.

View Rohit Sharma's current disclosures

Last revised:

14 Jan 2023, Rohit Sharma ◉

Disclosures:

At the time the article was last revised Rohit Sharma had no financial relationships to ineligible companies to disclose.

View Rohit Sharma's current disclosures

Revisions:

1 time, by 1 contributor - see full revision history and disclosures

Systems:

Central Nervous System

Sections:

Signs

Synonyms:

Black toe sign (brain)
Black toe sign (MELAS)

The black toenail sign is a radiological sign described in mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) on MRI.

The sign describes the subacute appearance of radiological correlates of stroke-like episodes, whereby there are small regions of deep cortical or juxtcortical T2/FLAIR hypointensity, surrounded by hyperintensity ^1,2. The hypointensity gives the appearance of a black toenail against the surrounding hyperintense toe ¹. It is thought that this hypointensity represents cortical laminar necrosis, which has been histologically proven to occur in MELAS ¹.