Caesarean scar pregnancy (CSP): a rare case of complete scar dehiscence due to scar ectopic pregnancy and its management

Abstract

We present a rare case of Caesarean scar pregnancy (CSP) in which the embryo implants within the myometrium at the site of a previous caesarean scar with complete scar dehiscence and its distinctive management. A 38-year-old G8P1 woman presented with vaginal bleeding following 6 weeks of amenorrhoea following IVF. Serum b-human chorionic gonadotropin (HCG) level was 9166 mIU/mL and transvaginal ultrasound (TVS) revealed (Fig. 1) an inhomogeneous fixed mass, 5 cm in size within the myometrium at her previous caesarean scar site extending outside the uterus through the caesarean scar and adjacent to the bladder; on the basis of this diagnosis CSP was made. Systemic methotrexate (MTX) was administered, (1 mg/kg intramuscular) and b-HCG level fell to 18.0 mIU/mL over 3 months follow-up. However, the patient continued to have lower abdominal pain and a repeat TVS showed the mass had reduced in size to 3.5 cm. Because of drawn out recovery period and as she wanted to go for another IVF cycle, laparoscopy was undertaken. After reflection of the bladder peritoneum, it was noted that the previous caesarean section scar had dehisced completely (Fig. 2a, b). The CSP mass was thus excised and the edges of the defect approximated in two layers. Postoperative course was unremarkable, and her b-hCG levels were \5 mIU/mL. The histopathology report confirmed diagnosis of CSP with evidence of placenta percreta. The first ever case of CSP was reported in 1978, and since then only 19 cases were reported until 2001 [1, 2], followed by sudden increase to 751 cases by 2011 [3]. With no evident mechanism for CSP yet understood, the finding in most of the cases reflect that implantation occurs at the site of a micro or macroscopic defect in the scar [4]. Commonest presentation of CSP is abdominal pain and bleeding [5]. CSP is a diagnosis on ultrasound visualisation of gestational sac at the level of internal os, penetrating the anterior uterine wall approaching the bladder [6]. CSP is more challenging to diagnose if only inhomogeneous mass of products of conception is present such as in this case, where use of Doppler helps [3, 4]. Possibility of CSP should be considered in women who have had a previous caesarean [7], as delay in diagnosis can lead to uterine rupture causing serious maternal morbidity and loss of future fertility. There is no consensus on the preferred mode of treatment [3, 8]. After discussing the various treatment modalities in the literature [2, 3, 5], as per patients choice our management started with a single dose of systemic MTX. But later laparoscopy showed a silent complete scar dehiscence, which could have possibly resulted in rupture and intraperitoneal bleeding. There are no other published case reports of concomitant CSP and silent scar dehiscence. Our case brings to light the possibility of dehiscence after MTX therapy that could have implications for future fertility. It highlights the importance of post treatment long term surveillance following MTX and in cases where there is slow resolution of the CSP mass. The incidence of CSP is likely to rise substantially in the near future as caesarean delivery rates continue to increase. Setting up multicentre collaboration would encourage robust evidence-based studies essential for making recommendations for practice. Until then, one has to rely on N. Agarwal A. Shahid (&) F. Odejinmi Whipps Cross University Hospital, Barts Health NHS Trust, London, UK e-mail: anupamashahid@gmail.com; anupamashahid@yahoo.com