Chronic tubal pregnancy manifesting as a heterogeneous adnexal mass with prominent neovascularization in a woman with a negative serum β-human chorionic gonadotropin level.

A 41-year-old woman (gravida 2, para 1) underwent elective termination of pregnancy at approximately 7 weeks of gestation. At 1 month after the elective abortion, she was referred due to abnormal results in a cervical cytological examination. Transvaginal ultrasonography showed a heterogeneous mass of 16 mm in diameter in the left adnexal region. At 3 months after her referral, the asymptomatic left adnexal mass had increased to 55 mm in diameter. Prominent vascular flow was detected in the solid portion by color Doppler ultrasonography. Magnetic resonance imaging showed suspected hemorrhage in the left adnexal cystic mass. Three-dimensional computerized tomographic angiography showed the prominent development of tortuous blood vessels in the left adnexal region, which originated from the left ovarian artery. The patient had a negative β-human chorionic gonadotropin (hCG) level. Left salpingectomy was performed by a single-port laparoscopic approach. A pathological examination revealed degenerated villous tissue with β-hCG-positive syncytiotrophoblasts.