Which MRI finding is pathognomonic of adenomyosis and distinguishes it reliably from uterine fibroids?

• A Uterine wall thickness > 12 cm
• B T2-hyperintense myometrial lesion with a well-defined pseudocapsule
• C Heterogeneous T1-hypointense lesions in the myometrium
• D Thickening of the junctional zone ≥ 12 mm with poor margination ✓

Explanation

On T2-weighted MRI, the junctional zone (the low-signal inner myometrium corresponding to compact smooth muscle) normally measures < 8 mm. A junctional zone thickness ≥ 12 mm is the MRI criterion most specific for adenomyosis, with poor, ill-defined margins and bright foci (heterotopic glands) within the thickened zone. Fibroids appear as well-defined T2-hypointense spherical masses with a pseudocapsule. T1-bright foci indicate haemorrhage within adenomyotic islands.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.