This obstetric ultrasound series (A-D) captures a rare twin pregnancy consisting of a complete hydatidiform mole and a coexisting viable fetus, spanning from 15 to 28 weeks of gestation. Image A (15 weeks) reveals a distinct cystic area at the anterior uterine wall characterized by multiple small, sonolucent vesicles, clearly separated from a homogeneous normal placenta. Image B (18 weeks) illustrates the characteristic heterogeneous, 'grape-like' vesicular echotexture of the hydatidiform mole situated superiorly, while a viable fetus with distinct anatomical outlines is visible inferiorly. Images C (24 weeks) and D (28 weeks) demonstrate the progression of the condition, showing the persistent, complex multicystic structure of the mole alongside the developing normal placenta and fetus. The series emphasizes the diagnostic hallmark of this condition: the presence of two distinct placental tissues—one with normal echogenicity and one exhibiting the disorganized, hydropic villi typical of molar pregnancy. This visual progression is critical for differentiating between a partial mole and a twin pregnancy with a complete mole and a coexistent live fetus.

This diagnostic image is a transvaginal ultrasound featuring a sagittal view of the uterus, demonstrating a partial hydatidiform mole. The image shows a heterogeneous intrauterine mass with a classic 'snowstorm' or 'bunch of grapes' appearance, characterized by multiple small, anechoic (black) cystic vesicles representing hydropic villi. A distinct anechoic gestational sac containing a small fetal pole or embryo is visible, which is the key diagnostic feature distinguishing a partial mole from a complete hydatidiform mole. A Color Doppler overlay is applied to a central region of interest, showing prominent vascularity (red and blue signals) within the deciduous and placental tissue, indicating active blood flow. The surrounding myometrium appears intact. This image is used in obstetrics and gynecology to illustrate gestational trophoblastic disease (GTD) and the importance of high-resolution ultrasound in differentiating between complete and partial molar pregnancies based on the presence of fetal tissue and placental morphology.

Diagnostic ultrasound image featuring a color Doppler study of a molar placenta, characteristic of a complete hydatidiform mole. The grayscale background reveals a heterogeneous, multicystic placental mass often referred to as a 'snowstorm' or 'swiss cheese' pattern. This is comprised of numerous small, anechoic vesicular structures representing hydropic villi. Superimposed color Doppler signals (red and blue) demonstrate active blood flow within the septations and around the cystic spaces, indicating significant vascularity of the molar tissue. This imaging modality is essential for distinguishing gestational trophoblastic disease from other uterine masses, such as degenerating fibroids or chorioangiomas. The clinical context involves a rare case of a twin pregnancy with a coexisting complete hydatidiform mole, where the diagnostic focus is on the distinct morphology of the abnormal third placental mass and its associated high vascularity.

Gross pathology photograph of gestational tissue from a 30-year-old woman at approximately 14 weeks gestation. The image demonstrates placental tissue with admixture of vesicular hydropic villi and areas of normal villous architecture, accompanied by focal blood clots. A live fetus with intact umbilical cord is present adjacent to the placental tissue, consistent with partial hydatidiform mole in which a triploid conceptus coexists with molar villi. The case description notes paternal duplication or dispermic fertilization as the cytogenetic basis for triploidy (commonly 69,XXY) and highlights distinguishing features of partial mole. Incomplete moles can progress to invasion in less than 5% of cases, whereas complete hydatidiform moles show higher risk of persistent trophoblastic disease and choriocarcinoma. The gross morphology in this specimen--mixed vesicular and solid villous components with hemorrhagic clots--reflects hydropic change and trophoblastic proliferation occurring within placental tissue. Clinically, the presentation includes amenorrhea, vaginal bleeding, and uterine enlargement; ultrasound may reveal abnormal placentation with an intrauterine fetus. Differential considerations include complete mole, choriocarcinoma, invasive mole, and other GTD entities. Management typically involves termination with subsequent surveillance for persistent gestational trophoblastic disease. Ancillary notes emphasize molecular cytogenetics for definitive classification when available.