Keywords
uterine artery embolization - enhanced myometrial vascularity - ectopic pregnancy
Introduction
Enhanced myometrial vascularity (EMV) is an uncommon entity that has been described
in association with uterine surgical interventions, retained products of conception
(RPOC), placental invasion abnormalities, gestational trophoblastic disease (GTD),
gynecological carcinomas, and cesarean scar pregnancy (CSP).[1] We describe a case of interstitial ectopic pregnancy complicated with uterine EMV
successfully managed with bilateral uterine arterial embolization (UAE). Interstitial
ectopic pregnancy is a rare occurrence and makes up only 2% of total ectopic pregnancies.
To the best of our literature search, this is a unique obstetric application of UAE.
Case Report
A 29-year-old nulliparous woman presented to the gynecology department with lower
abdominal pain. The pain was dull, below the umbilicus, moderate in intensity with
no signs of peritonitis. The patient had unprotected sexual intercourse in the last
2 months with a history of using levonorgestrel emergency contraceptive (LNG-EC).
She had no history of pelvic inflammatory disease, abortion, genital infections, or
surgical procedures. Transabdominal (TAS) and transvaginal (TVS) ultrasound (US) were
suggestive of a 4.2 × 4 cm eccentric, round, heterogeneous lesion with a central anechoic
area located in the right interstitial aspect of the myometrium ([Fig. 1A, C]). On Doppler US, the lesion demonstrated profusely high vascularity ([Fig. 1B, D]). Magnetic resonance imaging (MRI) revealed similar findings. Beta-human chorionic
gonadotropin (beta-HCG) was 2,400 mIU/mL. The diagnosis of interstitial ectopic pregnancy
with EMV was made.
Fig. 1 (A) Transabdominal ultrasound (right parasagittal view) reveals a round heterogeneous
isoechoic lesion with a central anechoic sac in the fundus region near the right interstitial
end. (B) Color Doppler revealed avid vascularity within the lesion. (C) Transvaginal sonography confirmed the predominant anechoic central areas within
the lesion in the right interstitial end with (D) avid vascularity in most of the lesion and adjacent myometrium on Doppler mode.
Owing to the highly vascular interstitial lesion with a risk of ectopic rupture, difficult
surgical resection due to location and vascularity, and the patient's wish to preserve
fertility, a referral was made to interventional radiology and UAE was planned.
Right transradial access was gained to perform angiography, followed by UAE. [Figs. 2] and [3] demonstrate bilateral hypertrophied uterine arteries and their tortuous branches
perfusing the hypervascular lesion ([Figs. 2A, B] and [3A, B]). UAE was performed bilaterally using 300- to 500μm embospheres. Postembolization
angiograms demonstrated complete occlusion of the perfusing arteries and subsequent
resolution of the EMV ([Figs. 2C, D] and [3C, D]). Follow-up TVS demonstrated a thrombosed lesion. Beta-HCG on days 2 and 7 postembolization
reduced to 627 and 423.7 mIU/mL, respectively. The patient resumed menstruation at
6 weeks with a negative beta-HCG and maintained regular menstruation at the 6 month
follow-up examination with no reported complications.
Fig. 2 Selective left internal iliac angiogram suggestive of (A) prominent hypertrophied spiral uterine arterial feeders terminating toward the right
hemipelvis (correlating with the lesion location). (B) The delayed angiogram phase reveals a round area of vascular blush. (C) Super-selective angiogram of the left uterine artery with a microcatheter placed
in the distal uterine artery confirmed the findings and was used for injecting embolic
particles. (D) Postembolization super-selective left uterine angiogram suggestive of absent blush
and hypertrophied arteries with stasis in the proximal uterine artery.
Fig. 3 Selective right internal iliac angiogram suggestive of (A) prominent hypertrophied spiral uterine arterial feeders terminating also toward
the right hemipelvis (correlating with the lesion location). (B) The delayed angiogram phase reveals a round area of vascular blush. (C) The serial delayed phase revealed opacification of draining right iliac veins. (D) Postembolization super-selective right uterine angiogram suggestive of absent blush
and hypertrophied arteries with stasis in the proximal uterine artery.
Discussion
Diagnosis of interstitial pregnancy requires high clinical suspicion as the patient
can be asymptomatic or present with vague abdominal pain, nausea, vomiting, or vaginal
bleeding. Tubal pregnancies in hemodynamically stable patients with no risk of rupture
are managed medically with intramuscular (IM) methotrexate or with laparoscopic surgery.[2] However, medical management of EMV is not recommended due to the increased risk
of life-threatening bleeding in unresolved lesions.[3] Studies have reported decreased complication rates and subsequent pregnancies after
selective UAE for interstitial pregnancies.[4]
RPOC are reported to be the most common cause of uterine EMVs. The clinical symptoms
of acquired uterine EMVs vary in severity and the progression can be sudden, which
may increase the need for invasive management due to the risk of development of hemodynamic
instability. Dilatation and curettage is commonly performed in unstable patients and
those refractory to medical management. UAE for acquired uterine EMV is described
in patients with underlying pathologies that are high risk and prone to rupture.
Our case was unique in presentation as the patient had no vaginal bleeding and no
history of previous abortions or surgery, excluding the risk factors generally associated
with the development of acquired uterine EMV. The history of LNG-EC use is a rare
cause of ectopic pregnancy. Despite the management challenges that come with interstitial
ectopic pregnancies due to the risk of significant complications, UAE proved to be
effective in treating ectopic pregnancy with EMV. Thus, UAE can be a safe, minimally
invasive, and fertility-preserving procedure for patients with high-risk underlying
pathologies.
Conclusion
Acquired uterine EMVs remain a rare entity possibly being underreported and underrecognized.
UAE is a successful fertility-preserving treatment option for hemodynamically stable
patients with underlying pathologies that are associated with a high risk of complications
following expectant or surgical management.
