Invasive molar pregnancy in rudimentary uterine horn

Incidence of molar pregnancy is 1-3/1000 pregnancies. Invasive mole is a local invasive form of gestational trophoblastic neoplasias which is mostly seen in reproductive age and usually follows a molar pregnancy and rarely has an initial presentation. Ectopic pregnancy in rudimentary uterine horn is extremely rare and is seen in 1/100,000 - 140,000 pregnancies. Invasive mole has seldom been reported in ectopic localizations but not in a patient with Müllerian duct anomaly. Here we represent a case of invasive mole in a reproductive age patient with unicornuate uterus and rudimentary communicating uterine horn. Invasive mole presented initially, mimicking ectopic pregnancy. The patient underwent diagnostic laparoscopy and resection of rudimentary uterine horn was performed. The pathology result was reported as an invasive mole. Serum b-hCG levels normalized on post-operative first month and no additional chemotherapy was needed.