Hydatidiform Mole (Partial)

Overview


Plain-Language Overview

Hydatidiform Mole (Partial) is a rare condition that affects the placenta, the organ that connects a developing baby to the mother during pregnancy. It occurs when there is an abnormal fertilization of the egg, leading to the growth of abnormal tissue instead of a normal fetus. This condition can cause symptoms such as vaginal bleeding, an unusually large uterus, and high levels of the pregnancy hormone hCG. The abnormal tissue can sometimes form cysts that look like a bunch of grapes. It mainly affects the reproductive system and can impact the health of the pregnancy and the mother. Early diagnosis is important to manage the condition and prevent complications.

Clinical Definition

Hydatidiform Mole (Partial) is a type of gestational trophoblastic disease characterized by abnormal proliferation of trophoblastic tissue and the presence of some fetal tissue. It results from fertilization of a normal ovum by two sperm (dispermy), leading to a triploid karyotype (usually 69,XXY or 69,XXX). The pathology shows focal hydropic swelling of chorionic villi with focal trophoblastic hyperplasia, distinguishing it from a complete mole. Clinically, it presents with vaginal bleeding, uterine enlargement inconsistent with gestational age, and elevated serum hCG levels, though typically lower than in complete moles. Partial moles carry a lower risk of persistent trophoblastic disease or malignancy compared to complete moles but require careful follow-up. Diagnosis and management are critical to prevent progression to invasive mole or choriocarcinoma.

Clinical Presentation


Diagnostic Workup


Pathophysiology


Treatments


Prevention


Outcome & Complications


Differential Diagnoses


Medical Disclaimer: The content on this site is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. If you think you may be experiencing a medical emergency, call 911 or your local emergency number immediately. Always consult a licensed healthcare professional with questions about a medical condition.

Artificial Intelligence Use: Portions of this site’s content were generated or assisted by AI and reviewed by Erik Romano, MD; however, errors or omissions may occur.

Analytics Disclosure: If you allow analytics cookies, Doctogenic uses Google Analytics, Microsoft Application Insights, and Microsoft Clarity to understand site usage, diagnose issues, review heatmaps and session replay recordings, and improve the service on pages where those tools are enabled. Clarity is not enabled on account, purchase, billing, checkout, Stripe-related, or admin pages. You can change this choice through Cookie preferences.

USMLE® is a registered trademark of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). Doctogenic and Roscoe & Romano are not affiliated with, sponsored by, or endorsed by the USMLE, FSMB, or NBME. Neither FSMB nor NBME has reviewed or approved this content. "USMLE Step 1" and "USMLE Step 2 CK" are used only to identify the relevant examinations.