Intramyometrial Pregnancy Presenting as Abnormal Uterine Bleeding in Perimenopausal Female.

Abnormal uterine bleeding (AUB) is frequently encountered in the gynecological complaint of perimenopausal female visiting the outpatient department. Beginning in mid-40s, perimenopause is often marked with menstrual irregularities. Intramyometrial pregnancy (IMP) is a rare type of ectopic pregnancy with an incidence of <1% of all ectopic gestation may present as AUB in perimenopausal female. It remains a diagnostic challenge, especially in background of negative pregnancy test with the lesion ultrasonographically mimicking a fibroid with or without degeneration or an adenomyoma. We report the case of a 41-year-old perimenopausal female presenting with AUB not responding to medical management and ultrasound suggestive of degenerative fibroid. Hence, total laparoscopic hysterectomy was done and histopathology revealed the lesion to be IMP. The aim of this case report is to consider this rare entity as a possible cause of AUB in perimenopausal female even in the pretext of negative pregnancy test. Copyright:

INTRODUCTION

An intramyometrial pregnancy (IMP) constitutes very rare type of ectopic pregnancy with <1% of all ectopic gestation.[1] It is located within the uterine wall surrounded by myometrium with complete separation from uterine cavity and fallopian tube.[2] Etiology includes uterine trauma as dilatation and curettage, lower uterine cesarean section (LSCS), myomectomy, manual removal of placenta resulting in sinus tract within the endometrium; in vitro fertilization (IVF) with difficult embryo transfer with false passage formation and implantation over intramyometrial adenomyotic foci, invasion of uterine wall by placenta accreta and subsequent growth of fetus deep within the myometrium.

CASE REPORT

A 41-year-old perimenopausal female with previous LSCS presented with continuous bleeding for 2 months not responding to medical management. Her previous cycles were regular with no missed period. The patient had one IVF conception followed by LSCS 15 years back. No history of any uterine procedures was given. The patient was using barrier contraceptive and gave a history of abstinence for the last 3 months. Per speculum examination was suggestive of normal-looking cervix with bleeding from the os, uniformly enlarged 8–10 weeks size uterus freely mobile, no cervical movement tenderness, and no adnexal mass on per vaginal evaluation. An ultrasound was suggestive of bulky uterus with entire myometrium anteriorly being replaced by poorly marginated, predominantly solid space-occupying lesion of 7 cm × 6 cm × 6.5 cm with echogenic areas and cystic foci suggestive of degenerated fibroid. The magnetic resonance imaging (MRI) revealed well-defined altered signal intensity lesion of size 6.6 cm × 7.1 cm × 7.7 cm in anterior myometrium appearing hyperintense on T2-weighted images distorting the endometrial cavity [Figure 1], suggesting of degenerated fibroid with intact cervix [Figure 2]. Her hematological evaluation was normal except for raised lactate dehydrogenase (LDH) levels (290 IL units per liter).

Figure 1

Sagittal T2-weighted image of uterus showing well-circumscribed heterogeneous mass (A) in anterior myometrium distorting the endometrial cavity with small portion normal myometrium at the fundus (B)

Figure 2

Sagittal T2-weighted image of the uterus with demarcated cervix

The patient refused for myomectomy. Considering age of the patient with large degenerative fibroid, no response to medical management (taken before present consultation) with raised LDH levels and no desire for future fertility patient opted for total laparoscopic hysterectomy. On laparoscopy well-defined soft hemorrhagic mass of 6 cm × 6 cm was seen in the uterus anteriorly. Total laparoscopic hysterectomy was done and intact specimen was sent for frozen section. Cut section showed a large hemorrhagic mass involving the uterine wall. As decided by tumor board, laparoscopy could be proceeded by laparotomy in case of any spill or inability to deliver uterus intact. Frozen section showed hematoma with pan myometrial chronic inflammation. Final histopathology suggested irregular endometrial surface with compressed proliferative endometrium, fibrinoid necrosis, marked chronic inflammation infiltrating into myometrium up to the serosal surface with focal chorionic villi [Figure 3] in blood clot suggestive of products of conception with no evidence of leiomyomatous tissue in the lesion. The presence of chorionic villi with the absence of leiomyomatous tissue in the uterine wall is sufficient for diagnosing it as IMP in reference to the cases in the literature so far.

Figure 3

Microscopic section showing chorionic villi within in blood clot suggestive of retained products of conception (H and E, ×40)

Serum beta-human chorionic gonadotropin (HCG) done in institutional laboratory was negative.

DISCUSSION

Abnormal uterine bleeding (AUB) accounts for more than 70% of all gynecological consultations in perimenopausal and postmenopausal age groups.[3] AUB accounts for two-thirds of all hysterectomies with uterine fibroid being the leading cause.[2] Clinical examination, investigations with imaging modalities help to find out the etiology. Ectopic pregnancy in perimenopausal female can be the cause of continued bleeding even without period of amenorrhea. Ectopic pregnancy is implantation and development of the blastocyst at a site other than normal implantation site of uterine cavity excluding angles of cavity and cervical canal. Nearly 95% of ectopic are of tubal origin and 5% are nontubal in origin. IMP is a rare type of ectopic with the incidence of <1% of all ectopic.[1]

World literature has only handful of cases reported with first case reported in 1913 by Doederlien and Herzog.[4] IMP refers to a uterine conception in the uterine wall surrounded by myometrium all around with complete separation and no connection to the uterine cavity, fallopian tubes, and round ligaments.[2] It rarely exceeds 12 weeks of gestation since the growth of pregnancy results in thinning of overlying myometrium predisposing uterine rupture with 2.5% of maternal mortality.[5]

Confusion remains in the literature as to its pathophysiology. Ong et al. explained intramyometrial ectopic by increased lytic activity of the syncytiotrophoblast and defective decidualization allowing the conceptus to penetrate the myometrium. In normal pregnancy, decidua attracts the trophoblast with both intravascular and interstitial invasion of the inner myometrium but without the movement of conceptus within the myometrium.[6]

Various risk factors have been identified for the movement of conceptus in myometrium resulting in intramyometrial gestation. The most common factor is uterine trauma such as in previous curettage, cesarean section, and myomectomy.[7] Difficult embryo transfer in IVF produces a false passage within the myometrium.[8] Leyder et al. described IMP after an embryo transfer following uterine artery embolization.[9] In our case, although there was a history of IVF conception followed by cesarean section 15 years back, however, its relevance with the present diagnosis could not be explained.

Treatment has to be individualized depending on the time of diagnosis, hemodynamic stability, and location of lesion with the depth of muscular invasion, gestational age, and desire for future fertility.

Negative beta-HCG cannot exclude an ectopic pregnancy. As in our case, pelvic MRI with negative beta-HCG was unable to differentiate between degenerative leiomyoma and IMP. Growth of trophoblast causes the erosion of vessels and hematoma formation with inflammation. Persistence of ectopic without rupture may lead to degeneration of trophoblast, hence, cessation of HCG production.[10]

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Nil.

Conflicts of interest

There are no conflicts of interest.