Ruptured rudimentary horn pregnancy misdiagnosed as ruptured pseudo aneurysm internal iliac artery.

Sir,

Congenital malformations of the uterus also known as mullerian duct anomalies are rare (1%). Unilateral arrest of mullerian duct development results in unicornuate uterus (∼1:250). Rarely, unicornuate uterus may also have a rudimentary horn (1:100,000) more on the right side. The pregnancy in a rudimentary horn is rare between 1/76,000 and 1/140,000 pregnancies and represent a form of ectopic gestation. The most significant threat of a rudimentary horn pregnancy is the risk of rupture because of the poorly developed musculature.[1]

A 30-year woman G2P1001, complained of severe abdominal pain with vomiting for last 5 days with history of 2½ month's amenorrhoea. The ultrasonography and computed tomography Angiography of the abdomen was done at another peripheral center and diagnosed as a case of right adnexal hematoma due to ruptured pseudo aneurysm of anterior branch of internal iliac artery. We reviewed the case and repeated ultrasonography and CT scan of abdomen along with the urine pregnancy test that was found positive. In CT scan uterus was empty with a large heterogenous mass present in right adnexa with multiple hypertrophied arteries supplying it with active contrast extravasation (suggestive of active bleeding), free fluid was present along with suspected fetal bones adjacent to right adnexal mass [Figure 1a and b]. The overall impression changed the final diagnosis to ruptured ectopic pregnancy. Clinical decision for emergency laparotomy was made. On general examination, the patient was conscious and oriented, her Hb 6.3 gm%, BP-98/60 mmHg, pulse rate-122/min, respiratory rate-12/min, rest of the examination and investigations were normal. On per abdomen examination scar of previous caesarean was present, a firm mass felt nearly up to the umbilicus, more on the right side, not mobile, and tenderness was present. On per vaginum examination bleeding was present, cervix long, directed backward, exact uterine size could not be made out, and a large immobile firm mass felt, which was tender.

Figure 1

(a) Coronal reconstructed CT angiography image shows hypertrophied uterine artery supplying the lesion (thin arrow). Fetal skeleton is seen lying in the right iliac fossa (thick arrow). (b) Non contrast axial CT image shows a large heterogeneous mass in midline and right side of abdominal cavity (star) with haemoperitoneum in the right iliac fossa. A fetal skeleton is seen lying in the right iliac fossa (arrow). (c) Fetus of 11 weeks found in pelvic cavity. (d) Excised ruptured rudimentary horn with right tube and ovary

Exploratory laparotomy was done under general anaesthesia. On opening of the abdomen haemoperitoneum with unicornuate uterus with rudimentary horn was present. The rudimentary horn of the uterus was ruptured and bleeding with a large amount of clots in the right adnexa. On removing of clots a fetus of approximately 11 weeks was recovered within the clots [Figure 1c]. Bleeding rudimentary horn was excised from the uterus along with right tube and ovary and stitched [Figure 1d]. Peritoneal lavage done and abdomen closed in layers. On earth post-operative day patient discharged with no complains.

Rupture of rudimentary horn of the uterus is one of the remote causes of an acute abdomen with pregnancy. However, missing the diagnosis can lead to fatal complications. In the present case, the patient was presented as a clinical emergency. Reports in the literature confirm that such pregnancies are known to last up to 20 weeks, while there are some cases with a total neonatal survival.[2] In such cases, termination of pregnancy and resection of the rudimentary horn would be lifesaving, in addition to avoiding subsequent pregnancies in the same horn.[3] The initial diagnosis of ruptured pseudoaneurysm was revised when the patient urine pregnancy test was positive, empty uterine cavity, symptoms of hypovolemia and intraabdominal bleeding on ultrasonography. However, in the present case, the associated risk appeared to be her history of one caesarean operation for breech presentation as an etiological factor. As the patient was hemodynamicaly unstable, the decision of laparotomy was chosen. Unicornuate uterus with rudimentary horn is associated with increase rate of abortions and miscarriages. However, missing the diagnosis can lead to fatal complications, while early detection can save the life of the patient.