Primary omental pregnancy on the gastrocolic ligament.

Abstract: Omental pregnancy is an extremely rare form of abdominal pregnancy. Only 16 cases had been reported in the literature, and most were secondary omental pregnancies. We presented a case of primary omental pregnancy located on "gastrocolic ligament" diagnosed at surgical operation. The aim of this presentation is to remember that pregnancy can exist in unusual localizations, so abdominal observation and examination is very important during operations.

Key Words: Ectopic pregnancy, omental pregnancy, gastrocolic ligament

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Abdominal pregnancy is a very rare and serious type of extrauterine gestation that accounts for approximately 1.4% of all ectopic pregnancies. The maternal mortality rate is seven times higher than in nonabdominal pregnancies and the clinical presentations are extremely variable. Omental pregnancy is an extremely rare form of abdominal pregnancy. To our knowledge, only 16 cases have been reported in the literature, and most were secondary omental pregnancies. We recently encountered a case of primary omental pregnancy located on the "gastrocolic ligament," a portion of the greater omentum passing from the greater curvature of the stomach and the first part of the duodenum to the transverse colon. The patient presented in acute shock due to intra-abdominal bleeding requiring emergency laparotomy. Omental pregnancies have been described, but to our knowledge, this is the first case report that describes and shows a pregnancy implanted on the gastrocolic ligament. As pregnancy can exist in unusual localizations, abdominal observation and examination is very important during surgical operations.

Case Report

A 35-year-old gravida 1, para 1 woman was admitted to the emergency room with complaints of dizziness and abdominal pain. Hypotension, abdominal tenderness and distention were noted on initial evaluation. She had regular menses and her last menstrual period was one month before, but she had very slight bleeding during her last period. She was using coitus interruptus as a contraceptive method. On gynecologic examination, a minimally enlarged uterus was noted. Her serum [beta]-hCG level was 122,000 mIU/mL. Serum hematocrit and leukocyte levels were 23% and 15,000 respectively. Transvaginal and abdominal ultrasonography revealed disseminated intra-abdominal fluid. Although the [beta]-hCG was positive, a gestational sac was not detected sonographically in the uterus. Both the ovaries were normal; however, the pouch of Douglas was filled with free fluid. We did not observe a 'tubal ring,' suggesting tubal pregnancy during ultrasound scan. A diagnosis of ectopic pregnancy with hemoperitoneum was made and fluid resuscitation was begun, followed by emergency laparotomy. There were 2 L of blood in the peritoneal cavity. After aspiration of the blood, both fallopian tubes were found to be normal in appearance. A general surgeon was consulted. During abdominal observation, a 3 X 3 cm bleeding mass was detected on the gastrocolic ligament. When we touched the mass, a gestational sac with the embryo came out (Fig.). The bleeding mass was grasped with 2 mosquitos, and was cut and tied with 2 to 0 Vicryl. It was resected completely and the bleeding stopped. Endometrial curettage was performed and reported as an "Arias-Stella reaction." The postoperative course was uncomplicated and the patient was discharged on postoperative Day 6. A gradual decrease in the [beta]-hCG was observed following the operation.

Discussion

Abdominal pregnancy is a very rare and serious type of extrauterine gestation that accounts for approximately 1.4% of all ectopic pregnancies. Omental pregnancy, an extremely rare form of abdominal pregnancy, can be primary or secondary, due to a tubal pregnancy that aborts out of the fimbria and reimplants in the peritoneal cavity. (1) The gastrocolic ligament is a portion of the greater omentum passing from the greater curvature of the stomach and the first part of the duodenum to the transverse colon. (2) The literature contains many case reports, including several unusual nidation sites, but to our knowledge, this is the first reported case of omental pregnancy implanted on the gastrocolic ligament. Abdominal pregnancies can be regarded as either primary or secondary, the latter most commonly associated with early tubal rupture and subsequent implantation on the peritoneal surface. (3) Primary abdominal pregnancy is much less common, and its diagnosis requires the establishment of the following criteria, as originally proposed by Studdiford (Thomas et al (4)) and later modified by Friedrich and Rankin (5): A) grossly normal tubes and ovaries, B) absence of uteroperitoneal fistula, and C) a pregnancy of less than 12 weeks gestational age, whose trophoblastic attachments are related solely to a peritoneal surface. In our case, surgical findings were consistent with Friedrich and Rankin's primary abdominal pregnancy criteria. Because of the high maternal and fetal morbidity and mortality, the pregnancy should be terminated as soon as diagnosed. (6) Therapy for ruptured ectopic pregnancy is generally surgical. Laparotomy is generally advised for hemodynamic instability. Treatment of unruptured ectopic pregnancy with methotrexate is an option for some patients with unruptured tubal pregnancy, (7) but can be complicated by abdominal pain in up to 60% of cases. (8)

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Conclusion

The case reported here demonstrates the occurrence of a rare form of abdominal pregnancy--an omental pregnancy which was primarily implanted on the gastrocolic ligament. There was no history or evidence of any of the commonly recognized etiologic factors which predispose to ectopic pregnancy, such as an intrauterine device, chronic pelvic inflammatory disease, previous infertility, or previous ectopic pregnancy. The only noted predisposing factors included allergies, including a latex allergy, and hypersensitivity to drugs. Due to the fact that pregnancy can exist in very unusual localizations, abdominal examination is very important during surgical operations.

References

1. Ozdemir I, Demirci F, Yucel O, et al. Primary omental pregnancy presenting with hemorrhagic shock: a case report. Gynecol Obstet Invest 2003;55:116-118.

2. Scandalakis JE. Surgical Anatomy and Technique. First edition. New York, Springer-Verlag, 1994.

3. Badria L, Amarin Z, Jaradat A, et al. Full-term viable abdominal pregnancy: a case report and review. Arch Gynecol Obstet 2003;268:340-342.

4. Thomas JS Jr, Willie JO, Clark JF. Primary peritoneal pregnancy. J Natl Med Assoc 1991;83:635-637.

5. Friedrich EG Jr, Rankin CA Jr. Primary pelvic peritoneal pregnancy. Obstet Gynecol 1968;31:649-653.

6. Cooray H, Harilall M, Farquhar CM. A six-year audit of the management of ectopic pregnancy. Aust N Z J Obstet Gynaecol 2002;42:538-542.

7. Olofsson JI, Poromaa IS, Ottander U, et al. Clinical and pregnancy outcome following ectopic pregnancy: a prospective study comparing expectancy, surgery and systemic methotrexate treatment. Acta Obstet Gynecol Scand 2001;80:744-749.

8. Carson SA, Buster JE. Ectopic pregnancy. N Engl J Med 1993;329:1174-1181.

Oznur Karaer, MD, Ozer Ilkgul, MD, and Semra Oruc, MD

From the Department of Obstetrics and Gynecology, Celal Bayar University, Manisa, Turkey.

Reprint requests to Dr. Semra Oruc, Zafer Cad No: 32/8 Bornova-Izmir, Turkey 35040. Email: [e-mail]

Accepted July 21, 2006.

RELATED ARTICLE: Key Points

* Omental pregnancy, an extremely rare form of abdominal pregnancy, can be either primary or secondary to a tubal pregnancy that aborts out of the fimbria and reimplants in the peritoneal cavity.

* Primary omental pregnancy can be located on the "gastrocolic ligament."