Transvaginal ultrasound of a 36-year-old woman with dysmenorrhoea shows asymmetrical myometrial thickening, several small anechoic myometrial cysts, and linear hyperechoic striations radiating from the endometrium into the myometrium. Which additional sonographic finding would further support the diagnosis of adenomyosis?
- A Fan-shaped shadowing arising from the myometrium ✓
- B A thin, uniformly echogenic endometrium
- C A discrete hypoechoic mass with circumferential flow on Doppler
- D Free fluid in the pouch of Douglas
Correct answer: A. Fan-shaped shadowing arising from the myometrium
Explanation
Fan-shaped or 'rainbow' acoustic shadowing emanating from the myometrium reflects the disordered smooth muscle architecture of adenomyosis and is a recognised direct sonographic criterion, alongside globular uterus, myometrial cysts, echogenic subendometrial lines and buds, and interrupted junctional zone. A discrete mass with peripheral Doppler flow describes a fibroid, free fluid is nonspecific, and endometrial echogenicity does not distinguish adenomyosis.
Reference: Williams Gynecology, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.