T2 dark spot sign (endometrioma)

Last revised by Yoshi Yu on 14 Mar 2025

T2 dark spot sign is an MRI appearance of endometriomas as a result of chronic hemorrhage. The sign is useful in differentiating a solitary endometrioma from a functional hemorrhagic ovarian cyst, as both might show high T1 signal with T2 shading

The sign describes a focal T2 hypointense nodule anywhere within a cyst, often against the wall, but not within the wall itself 3. It is presumed to represent a retracted blood clot containing high concentrations of iron and protein from recurrent hemorrhage 3.

T2 dark spot sign has high specificity (93%) in diagnosing endometriomas but lower sensitivity (36%). The T2 shading sign has high sensitivity (93%) and lower specificity (45%) 1.

Differential diagnosis

This sign can also be seen in cystic ovarian tumors like serous cystadenomas, in which the T2 dark spot is part of a hemorrhagic tumor or calcification 1,2.

See also

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