The chorionic bump: Radiologic and pathologic correlation.

Chorionic bump is a rare abnormal condition of the gestational sac seen in the first trimester of pregnancies, extending from the choriodecidual surface to the gestational sac. We report the sonographic and histopathologic findings in a case involving three "chorionic bumps" extending from the choriodecidual surface to the gestational sac. Chorionic bump can be associated with a poor prognosis for the pregnancy. Therefore, cases with chorionic bumps must be followed with serial ultrasound examinations throughout the first trimester.