Question:medium
A 35 year old nullipara female presented with dull aching pain with exacerbation during menstrual cycle. Usg reveals a heterogenous mass in right adnexa. Mri reveals a 4 x 5 cm T1 hyperintense mass with no suppression on fat started images. T2 weighted images show low signal with Dark shading. Diagnosis?
A 35 year old nullipara female presented with dull aching pain with exacerbation during menstrual cycle. Usg reveals a heterogenous mass in right adnexa. Mri reveals a 4 x 5 cm T1 hyperintense mass with no suppression on fat started images. T2 weighted images show low signal with Dark shading. Diagnosis?
Show Hint
T1 bright that does NOT suppress on fat sat = blood, not fat; add cyclical pain and 'T2 shading' and you have a chocolate cyst.
Updated On: Jun 22, 2026
- Dermoid cyst
- Endometrioma
- Ovarian cancer
- Para Ovarian Cyst
Show Solution
The Correct Option is B
Solution and Explanation
Solve it as a signal-intensity discriminator problem.
Two ovarian masses light up on $T1$: a dermoid (fat) and an endometrioma (blood). The single test that separates them is fat suppression - fat goes dark, blood stays bright. The stem hands you the discriminator directly: the mass is $T1$ bright and does NOT lose signal on fat-saturated images, so its content is blood, not fat. That immediately favours an endometrioma over a dermoid.
Confirm with the T2 behaviour.
The mass is described as low signal with "dark shading" on $T2$. T2 shading is the textbook endometrioma sign: cyclical bleeding deposits iron-rich, high-protein degraded blood that shortens $T2$ and dims the normally bright cyst fluid. A simple cyst would stay uniformly bright on $T2$.
Tie it back to the history.
The patient has dull pelvic pain that flares with menstruation. Endometriotic tissue is hormonally responsive and bleeds each cycle, which is exactly why the pain is cyclical and why the cyst accumulates the blood products that produce the imaging signature ("chocolate cyst").
Rule out the rest.
$\bullet$ Dermoid: $T1$ bright but suppresses with fat sat - excluded by the stem.
$\bullet$ Ovarian cancer: expects solid/papillary enhancing tissue and septa, not pure haemorrhagic shading, and the benign cyclical history fits poorly.
$\bullet$ Para-ovarian cyst: a simple cyst that follows fluid ($T1$ dark, $T2$ bright) - wrong signal entirely.
Diagnosis: Endometrioma (B).
Two ovarian masses light up on $T1$: a dermoid (fat) and an endometrioma (blood). The single test that separates them is fat suppression - fat goes dark, blood stays bright. The stem hands you the discriminator directly: the mass is $T1$ bright and does NOT lose signal on fat-saturated images, so its content is blood, not fat. That immediately favours an endometrioma over a dermoid.
Confirm with the T2 behaviour.
The mass is described as low signal with "dark shading" on $T2$. T2 shading is the textbook endometrioma sign: cyclical bleeding deposits iron-rich, high-protein degraded blood that shortens $T2$ and dims the normally bright cyst fluid. A simple cyst would stay uniformly bright on $T2$.
Tie it back to the history.
The patient has dull pelvic pain that flares with menstruation. Endometriotic tissue is hormonally responsive and bleeds each cycle, which is exactly why the pain is cyclical and why the cyst accumulates the blood products that produce the imaging signature ("chocolate cyst").
Rule out the rest.
$\bullet$ Dermoid: $T1$ bright but suppresses with fat sat - excluded by the stem.
$\bullet$ Ovarian cancer: expects solid/papillary enhancing tissue and septa, not pure haemorrhagic shading, and the benign cyclical history fits poorly.
$\bullet$ Para-ovarian cyst: a simple cyst that follows fluid ($T1$ dark, $T2$ bright) - wrong signal entirely.
Diagnosis: Endometrioma (B).
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