Chronic Ectopic Pregnancy Masquerading as Pelvic Inflammatory Disease: A Diagnostic Challenge

Abstract

Ectopic pregnancy is a potentially life-threatening condition that may be difficult to recognise when classical symptoms are absent. Chronic ectopic pregnancy can resemble pelvic inflammatory disease because both conditions may present with lower abdominal pain, cervical motion tenderness, and an adnexal abnormality. This report describes a 26-year-old woman who presented with mild lower abdominal pain and delayed menstruation for two weeks, without vaginal bleeding or haemodynamic instability. Pelvic examination revealed mild cervical motion tenderness, initially raising suspicion of pelvic inflammatory disease. A urine pregnancy test was positive, and the serum beta-human chorionic gonadotropin concentration was 1,245 mIU/mL. Transvaginal ultrasonography demonstrated an empty uterine cavity, a right adnexal mass measuring 3.1 × 2.7 cm, and minimal free fluid in the pouch of Douglas. These findings supported a diagnosis of chronic ectopic pregnancy. The patient fulfilled the reported criteria for conservative treatment and received a single intramuscular dose of methotrexate at 50 mg/m². Serial serum beta-human chorionic gonadotropin concentrations declined to 890 mIU/mL on Day 4, 420 mIU/mL on Day 7, and less than 5 mIU/mL by Week 4. She remained clinically stable and experienced complete resolution without reported complications. This case demonstrates the diagnostic overlap between chronic ectopic pregnancy and pelvic inflammatory disease and supports early pregnancy testing, transvaginal ultrasonography, and serial biochemical monitoring in women of reproductive age with non-specific pelvic symptoms.