Gestational Trophoblastic Neoplasia Heterogeneous Uterine Mass
medium
baby OBG
A 32-year-old woman presents 11 weeks after surgical evacuation of a complete hydatidiform mole with persistently elevated beta-hCG (plateau at 5,800–6,400 mIU/mL over 3 weeks), meeting FIGO criteria for post-molar gestational trophoblastic neoplasia. Transvaginal ultrasonography is performed. The structure marked **A** in the diagram shows a heterogeneous myometrial mass with vesicular cystic spaces. Which of the following best describes the pathological basis of this ultrasound finding in gestational trophoblastic neoplasia?
A. Myometrial adenomyosis with cystic degeneration secondary to chronic endometritis
B. Retained products of conception with secondary inflammatory oedema and myometrial hypertrophy
C. Uterine arteriovenous malformation with pseudoaneurysm formation and intramural haematoma
D. Invasion and proliferation of abnormal trophoblastic tissue with areas of haemorrhage and necrosis within the myometrium
Explanation
Why "Invasion and proliferation of abnormal trophoblastic tissue with areas of haemorrhage and necrosis within the myometrium" is right
The heterogeneous myometrial mass with vesicular cystic spaces (marked A) is the hallmark greyscale ultrasound finding of invasive molar pregnancy and post-molar gestational trophoblastic neoplasia. This appearance reflects direct invasion of abnormal trophoblastic cells into the myometrium, with interspersed areas of haemorrhage, necrosis, and cystic degeneration. According to Berek and Novak's Gynecology (16th Edition), this heterogeneous echotexture with cystic spaces represents the pathological infiltration of trophoblastic tissue into the myometrial layers, which is the defining feature of invasive mole and persistent GTN. The vesicular appearance corresponds to the abnormal chorionic villi and trophoblastic proliferation within the myometrial stroma.
Why each distractor is wrong
Retained products of conception with secondary inflammatory oedema and myometrial hypertrophy: While retained products can cause myometrial enlargement, they do not produce the characteristic heterogeneous mass with vesicular cystic spaces seen in GTN. Retained products typically appear as echogenic material within the endometrial cavity, not as an invasive myometrial lesion. This finding would be expected in incomplete evacuation, not in post-molar GTN with persistently elevated hCG.
Myometrial adenomyosis with cystic degeneration secondary to chronic endometritis: Adenomyosis presents with diffuse myometrial thickening and small cystic spaces, but does not produce the focal heterogeneous mass with the degree of vascularity and architectural distortion seen in GTN. Adenomyosis is not associated with elevated hCG and would not explain the clinical presentation of post-molar disease.
Uterine arteriovenous malformation with pseudoaneurysm formation and intramural haematoma: While colour Doppler in GTN does show intense vascularity with low-resistance flow (marked B), the greyscale finding of heterogeneous mass with vesicular spaces is not explained by AVM alone. AVM typically presents as a focal vascular lesion without the characteristic trophoblastic infiltration pattern seen here.
High-YieldNEET PG
The heterogeneous myometrial mass with vesicular cystic spaces on transvaginal ultrasound is pathognomonic for invasive molar pregnancy and post-molar GTN, reflecting direct trophoblastic invasion with haemorrhage and necrosis—the key greyscale finding that distinguishes GTN from other causes of myometrial pathology.
Berek and Novak's Gynecology, 16th Edition, Chapter on Gestational Trophoblastic Disease
Practice similar questions
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.
