History
A 6-year-old 4.6-kg (10.1-lb) spayed female Miniature Poodle was evaluated because of intermittent vomiting for approximately a week. The dog had been adopted 2 weeks prior to hospital admission, and no other medical history was known.
On physical examination, the dog was bright, alert, and responsive and was estimated to be 5% dehydrated. A healed ovariohysterectomy incision site that was mildly swollen and erythematous was noted, and the patient's nipples were prominent. A firm, nonpainful mass was palpated within the midabdomen. The only additional notable physical examination findings included moderate dental disease and mild lenticular sclerosis in the right eye.
Serum biochemical analysis and CBC results were evaluated 1 week prior to hospital admission and revealed a mild reticulocytosis; all other measurements were within reference limits. Radiographs of the abdomen were obtained (Figure 1).
Right lateral (A) and ventrodorsal (B) radiographic views of the abdomen of a 6-year-old 4.6-kg (10.1-lb) spayed female Miniature Poodle with a history of intermittent vomiting for 1 week.
Citation: Journal of the American Veterinary Medical Association 248, 11; 10.2460/javma.248.11.1231
Right lateral (A) and ventrodorsal (B) radiographic views of the abdomen of a 6-year-old 4.6-kg (10.1-lb) spayed female Miniature Poodle with a history of intermittent vomiting for 1 week.
Citation: Journal of the American Veterinary Medical Association 248, 11; 10.2460/javma.248.11.1231
Right lateral (A) and ventrodorsal (B) radiographic views of the abdomen of a 6-year-old 4.6-kg (10.1-lb) spayed female Miniature Poodle with a history of intermittent vomiting for 1 week.
Citation: Journal of the American Veterinary Medical Association 248, 11; 10.2460/javma.248.11.1231
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Radiographic Findings and Interpretation
A solitary mass lesion in the cranioventral portion of the abdomen, at the level of the second to fifth lumbar vertebrae, is observed on both projections and appears to be a fetus (Figure 2). The mass is circular on the lateral projection and ovoid on the ventrodorsal projection. A skull and long bones are clearly seen as mineral opacities within the mass and, on both projections, are associated with areas of apparent bone lysis. The fetal skeleton is collapsed, and on the lateral projection, the vertebral column is severely flexed. Caudodorsally, a focal discontinuity of the cranium, compatible with a fracture, is present. The fetus is surrounded by a thin soft tissue opacity capsule (approx 4 mm in thickness).
Same radiographic images as in Figure 1. Notice the solitary fetus with a mineralized skeleton in the cranial aspect of the abdomen (white arrowhead). No evidence of a uterus or signs of peritoneal effusion are evident.
Citation: Journal of the American Veterinary Medical Association 248, 11; 10.2460/javma.248.11.1231
Same radiographic images as in Figure 1. Notice the solitary fetus with a mineralized skeleton in the cranial aspect of the abdomen (white arrowhead). No evidence of a uterus or signs of peritoneal effusion are evident.
Citation: Journal of the American Veterinary Medical Association 248, 11; 10.2460/javma.248.11.1231
Same radiographic images as in Figure 1. Notice the solitary fetus with a mineralized skeleton in the cranial aspect of the abdomen (white arrowhead). No evidence of a uterus or signs of peritoneal effusion are evident.
Citation: Journal of the American Veterinary Medical Association 248, 11; 10.2460/javma.248.11.1231
No radiographic evidence of a uterine body or horns is apparent in the patient. Enlargement of the nipples is evident on the lateral projection. No radiographic abnormalities in the gastrointestinal tract, urinary tract, liver, or spleen were detected. Thoracic radiography was performed, and the findings were unremarkable.
Abdominal ultrasonography was performed to further characterize the location of the fetus and rule out the presence of uterine or ovarian remnants. A wellencapsulated mineralized fetus was identified slightly left of midline within the peritoneal cavity (Figure 3). The fetus was in an abnormal posture, characterized by an extremely flexed orientation. A fetal heartbeat or vascular flow was not detected on color flow Doppler ultrasonography. No evidence of amniotic fluid, mesenteric steatitis, or peritoneal effusion was detected. The uterine stump appeared hypoechoic and tubular and was 4 to 5 mm thick. Uterine horns and ovaries were not detected on ultrasonographic examination.
Transverse abdominal ultrasonographic image of the fetus of the dog in Figure 1. Notice the hyperechoic shadowing structures compatible with fetal skeleton and the absence of amniotic fluid. Scale on the right indicates length in centimeters.
Citation: Journal of the American Veterinary Medical Association 248, 11; 10.2460/javma.248.11.1231
Transverse abdominal ultrasonographic image of the fetus of the dog in Figure 1. Notice the hyperechoic shadowing structures compatible with fetal skeleton and the absence of amniotic fluid. Scale on the right indicates length in centimeters.
Citation: Journal of the American Veterinary Medical Association 248, 11; 10.2460/javma.248.11.1231
Transverse abdominal ultrasonographic image of the fetus of the dog in Figure 1. Notice the hyperechoic shadowing structures compatible with fetal skeleton and the absence of amniotic fluid. Scale on the right indicates length in centimeters.
Citation: Journal of the American Veterinary Medical Association 248, 11; 10.2460/javma.248.11.1231
Radiographic and ultrasonographic findings were compatible with an ectopic pregnancy, which resulted in a nonviable fetus that died at an advanced stage of gestation.
Treatment and Outcome
An exploratory laparotomy was performed. An encapsulated fetus was found adhered to the mesentery, which was carefully dissected and removed. A small adhesion was present between the uterine stump and mesentery; however, this was not associated with the fetus. No persistent or remnant uterine or ovarian tissue was found. The uterine stump appeared normal. No signs of peritonitis were present, and all other abdominal viscera were grossly normal. At 2 weeks after surgery, the dog was recovering well and was no longer vomiting. It is unknown whether the presence of the fetus was related to the clinical signs of vomiting.
Histologic examination of the fetus determined that it had a gestational age of 45 to 50 days. The fetus had autolyzed internal organs and arthrogrypotic limbs. All findings indicated that the fetus resulted from an ectopic pregnancy and was present at the time of ovariohysterectomy.
Comments
For the dog of the present report, radiographically apparent mineralized humeri and femurs indicated that the gestational age of the fetus was between 46 days and full term.1 Ectopic pregnancies are defined by finding an embryo or fetus outside of the uterus.2 This is a rare occurrence in dogs; however, when it does occur, the most common location for the fetus is within the peritoneal space. The most common cause of ectopic pregnancy in dogs is uterine wall rupture due to devitalized tissue from infection, trauma, or straining during parturition.2 Dogs with ectopic pregnancy most commonly have no clinical signs of illness, and the ectopic pregnancy is an incidental finding. Surgery is the treatment of choice for ectopic pregnancy, and dogs have an excellent prognosis.2 Ectopic pregnancy occurs in cats as well, most often secondary to traumatic uterine rupture, and the fetus is usually mummified in the peritoneal cavity at the time of diagnosis.3
Surgical findings in the dog of the present report revealed no evidence of peritonitis, and the uterus and ovaries were not present. Unfortunately, no prior medical or surgical records were available; therefore, the gross appearance of the uterus at the time of ovariohysterectomy is unknown. The fetus may have been in the peritoneal cavity at the time of ovariohysterectomy or, alternatively, the ovariohysterectomy procedure may have resulted in the fetus being dislodged into the peritoneal cavity; therefore, it is not possible to determine the precise cause of the ectopic pregnancy in the dog of the present report. Additional information such as whether the fetus was alive prior to the ovariohysterectomy is also unknown.
An abundance of information about ectopic pregnancies is available in human medicine, where it accounts for approximately 2% of pregnancies. As in veterinary medicine, abdominal ultrasonography is the modality of choice in human medicine to confirm the diagnosis of ectopic pregnancy.4–6 Unlike dogs, the most common location for ectopic pregnancy in humans is the fallopian tubes. Risk factors for ectopic pregnancy in humans include the following: gynecological surgery, use of intrauterine devices, congenital or acquired uterine anomalies, and others.4,5 The limited information in the veterinary literature means specific risk factors for ectopic pregnancy in dogs have not yet been established.
References
1. Concannon PRendano V. Radiographic diagnosis of canine pregnancy: onset of fetal skeletal radiopacity in relation to times of breeding, pre-ovulatory luteinizing hormone release, and parturition. Am J Vet Res 1983;44:1506–1511.
2. Eddey PD. Ectopic pregnancy in an apparently healthy bitch. J Am Anim Hosp Assoc 2012;48:194–197.
3. Rosset EGalet CBuff S. A case report of an ectopic fetus in a cat. J Feline Med Surg 2011;13:610–613.
4. Lin EPBhatt SDogra VS. Diagnostic clues to ectopic pregnancy. Radiographics 2008;28:1661–1671.
5. Murray HBaakdah HBardell T, et al. Diagnosis and treatment of ectopic pregnancy. CMAJ 2005;173:905–912.
6. Levine D. Ectopic pregnancy. Radiology 2007;245:385–397.
