Intramyometrial pregnancy

Author Information
Kumari M*, Gupta AS**
(* Third Year Resident, ** Professor
Department of Obstetrics and Gynaecology, Seth G.S. Medical College and K.E.M Hospital, Mumbai, India.)
An interesting case of  intramyometrial pregnancy managed conservatively with methotrexate is reported. Patients condition was not diagnosed for 9 months. She underwent multiple Dilatation and curettage procedures for retained products of conception and was again misdiagnosed as a case of arterio-venous malformation for which she was referred to us; a clinical suspicion combined with a MRI confirmed the suspicion of an intramyometrial pregnancy. As the patient was young and desired childbearing and was averse to further surgical management she was successfully managed by methotrexate.
Intramyometrial pregnancy or intramural pregnancy is a rare type of ectopic pregnancy and is very difficult to diagnose. Its exact incidence is unknown due to its rare occurrence and the fact that only isolated case reports are  documented  till date. The fertilized ovum or the conceptus implants in the myometrium and the gestational sac is located within the uterine wall wholly surrounded by the myometrium and unconnected to the uterine cavity, fallopian tube, or round ligament.[1]

Case Report
  A 26 years old gravid 2, abortion 1 was referred to us in February 2013  in view of uterine arteriovenous malformation. She complained of pain in abdomen and 6 weeks of amenorrhea. Her menstrual cycles had been irregular for preceding 9 months.  She had undergone a blunt curettage in April 2012 after a spontaneous abortion. Curettings were not sent for histopathological examination. Dilatation and curettage was again done in July 2012 as she continued to bleed irregularly, ultrasonography suggested retained products of conception and serum β-HCG level was 25,000 mIU/ml.  The procedure was repeated by another consultant. Histopathological report showed no chorionic villi. Her complaints persisted. A pelvic ultrasonography in December 2012 showed uterine arterio-venous malformation and she was then referred to us. Her vital parameters were within normal limits. General and systemic examination showed no abnormality. She was mildly anaemic. Her abdomen was soft. Vaginal examination showed no pelvic tenderness or masses. The uterus was of 12 weeks size, fundus bulky, soft, and anteverted. There was no active bleeding. Ultrasonography showed retained products of conception. Serum β-HCG value was 25,900 mIU/ml. Her haematological indices, serum chemistry, and chest radiograph were all within normal parameters. With a diagnosis of an incomplete abortion, a blunt curettage was done. In view of scanty curettage sample, an intramyometrial pregnancy was suspected. MRI was done. It showed a well defined rounded lesion seen in anterior myometrium measuring  3.36x3.23x2.9 cm size in anteroposterior, transverse and longitudinal dimensions. Multiple cystic spaces are seen within it with foci of haemorrhage. Post contrast imaging revealed peripheral enhancement of the lesion with homogenous enhancement of the rest of the lesion. Endometrial cavity was empty and not connected to the this mass. Engorged parametrial vessels were seen on the left side. Both ovaries were normal. These findings were suggestive of  an  intramyometrial pregnancy with cystic changes and haemorrhage inside. Histopathological study of the curetting’s did not show any chorionic villi.
Figure 1. MRI of the uterus. C: is the empty endometrial cavity; IM:  the intramural pregnancy in its Gestational sac.
In view of stable condition of patient and patient and her husband’s desire for future childbearing and her aversion to further surgery conservative management was started. Methotrexate 50mg/m 2 was administered intramuscularly. Her serial serum β-HCG  values fell progressively reaching less than1.2 mIU/ml at end of 3 months. Ultrasonography at that time showed calcification of lesion which had decreased in size  to 2x2 cm . Her regular menstrual cycles resumed.
An intramyometrial pregnancy is associated with factors causing trauma to the endometrium disrupting its continuity thus technically creating a path for the conceptus to gain entry into the myometrium for implantation. Such trauma occurs in a caesarean section , curettage, misplaced IUD, adenomyosis, placenta accreta, and necrosis of a uterine leiomyma after uterine artery embolization.[2, 3, 4] It may follow in vitro fertilisation.[5] Usually the diagnosis of intramural pregnancy cannot be made until uterine rupture  occurs, which usually occurres between about 11 and 30 weeks of  gestation. An intramural pregnancy is difficult to be  seen on  ultrasonography and  is easily confused with  a degenerating myoma , products of conception or congenital uterine anomaly.[3,5] In a hemodynamically stable patient who wants a future pregnancy, this condition  can be managed conservatively by local administration of KCL or Methotrexate or by systemic methotrexate either in single dose or as multiple dose regimen. [2,6,7,8] A  nonradical  surgical management in form of wedge resection or enucleation with myometrial reconstruction can be performed too. A patient with uterine rupture and hemodyamic instability requires a hysterectomy.

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Kumari M, Gupta AS. Intramyometrial pregnancy. JPGO 2014 Volume 1 Number 1 Available from: