History
A 13-year-old 7.1-kg (15.6-1b) sexually intact female Maltese had a 9-month history of a left inguinal hernia. On recent palpation by the referring veterinarian, the content within the hernial sac was suspected to be the urinary bladder and was reduced into the abdomen.
At the time of referral and hospital admission, the hernia was no longer reducible and had increased in size since being examined by the referring veterinarian. On physical examination, the patient was bright, alert, and responsive. A bilobed inguinal mass (8 × 8 cm) was noted; it was firm, rounded, and movable but could not be easily traced to the left inguinal ring. A 2 × 2-cm, firm mammary gland mass was also noted on the left mammary chain in the midabdomen cranial to the inguinal mass. There was no evidence of vaginal discharge. Findings on CBC and serum biochemical analysis revealed mild neutrophilia (14,720 neutrophils/μL; reference range, 3,000 to 11,500 neutrophils/μL), slightly low BUN (7 mg/dL; reference range, 8 to 24 mg/dL) concentration, and a high globulin (5.3 g/dL; reference range, 2.1 to 4.3 g/dL) concentration. Abdominal radiography was performed (Figure 1).
Right lateral (A) and ventrodorsal (B) abdominal radiographic views of a 13-year-old 7.I-kg (15.6-Ib) sexually intact female Maltese with a 9-month history of a left inguinal hernia
Citation: Journal of the American Veterinary Medical Association 253, 3; 10.2460/javma.253.3.265
Right lateral (A) and ventrodorsal (B) abdominal radiographic views of a 13-year-old 7.I-kg (15.6-Ib) sexually intact female Maltese with a 9-month history of a left inguinal hernia
Citation: Journal of the American Veterinary Medical Association 253, 3; 10.2460/javma.253.3.265
Right lateral (A) and ventrodorsal (B) abdominal radiographic views of a 13-year-old 7.I-kg (15.6-Ib) sexually intact female Maltese with a 9-month history of a left inguinal hernia
Citation: Journal of the American Veterinary Medical Association 253, 3; 10.2460/javma.253.3.265
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Diagnostic Imaging Findings and Interpretation
On abdominal radiographs (Figure 2), an enlarged liver with rounded, lobulated margins is evident. The enlarged liver is causing caudal displacement of the gastric axis, small intestines, and transverse colon. In the area of the mammary glands and inguinal lymph nodes, several rounded to convex soft tissue opacity masses are observed ventrally. Smooth new bone is present along the right ilial body, and the right ilial wing is irregularly marginated.
Same radiographic images as in Figure 1. Notice the enlarged liver with rounded, lobulated margins (thick arrows) and the rounded to convex soft tissue opacity mass along the caudoventral body wall (thin arrows).
Citation: Journal of the American Veterinary Medical Association 253, 3; 10.2460/javma.253.3.265
Same radiographic images as in Figure 1. Notice the enlarged liver with rounded, lobulated margins (thick arrows) and the rounded to convex soft tissue opacity mass along the caudoventral body wall (thin arrows).
Citation: Journal of the American Veterinary Medical Association 253, 3; 10.2460/javma.253.3.265
Same radiographic images as in Figure 1. Notice the enlarged liver with rounded, lobulated margins (thick arrows) and the rounded to convex soft tissue opacity mass along the caudoventral body wall (thin arrows).
Citation: Journal of the American Veterinary Medical Association 253, 3; 10.2460/javma.253.3.265
On the basis of radiographic findings involving the liver, the primary rule out was hepatic neoplasia. Lesser consideration was given to metastatic neoplasia, hepatic abscess, hematoma, or nodular regeneration. The masses along the mammary chain and in the left inguinal region were attributed to the inguinal hernia noted in the clinical history or to mammary neoplasia. The bony changes along the right ilium were likely a result of previous, unrelated trauma. No abnormalities were detected on thoracic radiography (images not shown).
Abdominal ultrasonography (images not shown) was performed to further evaluate the liver and left inguinal region. A large fluid-filled mass was found in the liver on the right and was suspected to be a primary hepatic tumor with lesser consideration given to an abscess. The left ovary was ultrasonographically normal. The right ovary was not identified. In the caudal portion of the abdomen, there was a large, round-to-tubular structure that was filled with echogenic fluid. This structure was connected by a stalk to a similar structure in the subcutaneous tissues of the left inguinal region. The most likely organ of origin for the fluid-filled tubular structure was the uterus. The primary differential diagnosis for dilation of the uterus with echogenic fluid was pyometra with inguinal herniation. Hemometra, mucometra, and hydrometra were considered less likely.
Abdominal CT was performed (Figure 3). A large, well-demarcated, smooth to slightly irregularly marginated, rounded, mixed soft tissue and fluid dense mass was found to originate from the right side of the liver, most likely from the right medial or caudate lobe. The primary differential diagnosis for this hepatic mass was primary neoplasia, such as hepatocellular carcinoma, or benign neoplasia, such as hepatoma or adenoma. The left ovary appeared normal on CT. However, the right ovary was caudoventrally displaced. A large, thin-walled, round, fluid-filled structure surrounded by a mildly contrast-enhancing band of soft tissue was identified adjacent to the urinary bladder. A similar structure was seen within the subcutaneous tissues outside the body wall in the left inguinal region. A hyperdense, contrast-enhancing band of soft tissue connected this structure to the other fluid-filled structure in the caudal portion of the abdomen on the right, which further supported the diagnosis of pyometra with concurrent inguinal herniation of the uterus.
Postcontrast parasagittal (A) and transverse (B) CT images of the abdomen of the dog in Figure 1. Notice the smoothly marginated, round, fluid-filled mass with a thin contrast-enhancing rim originating in the right side of the liver (thick arrows). Notice the large, thin-walled, fluid-filled tubular structure in the caudal portion of the abdomen, which is herniated through the body wall into the left inguinal region (thin arrows). The wall of this structure has contrast enhancement. The intra-abdominal and inguinal portions of the tubular structure are connected by a contrast-enhancing band of soft tissue (thick notched arrows). Images are displayed in a soft tissue window (window width, 500 Hounsfield units [HU]; window level, 30 HU).
Citation: Journal of the American Veterinary Medical Association 253, 3; 10.2460/javma.253.3.265
Postcontrast parasagittal (A) and transverse (B) CT images of the abdomen of the dog in Figure 1. Notice the smoothly marginated, round, fluid-filled mass with a thin contrast-enhancing rim originating in the right side of the liver (thick arrows). Notice the large, thin-walled, fluid-filled tubular structure in the caudal portion of the abdomen, which is herniated through the body wall into the left inguinal region (thin arrows). The wall of this structure has contrast enhancement. The intra-abdominal and inguinal portions of the tubular structure are connected by a contrast-enhancing band of soft tissue (thick notched arrows). Images are displayed in a soft tissue window (window width, 500 Hounsfield units [HU]; window level, 30 HU).
Citation: Journal of the American Veterinary Medical Association 253, 3; 10.2460/javma.253.3.265
Postcontrast parasagittal (A) and transverse (B) CT images of the abdomen of the dog in Figure 1. Notice the smoothly marginated, round, fluid-filled mass with a thin contrast-enhancing rim originating in the right side of the liver (thick arrows). Notice the large, thin-walled, fluid-filled tubular structure in the caudal portion of the abdomen, which is herniated through the body wall into the left inguinal region (thin arrows). The wall of this structure has contrast enhancement. The intra-abdominal and inguinal portions of the tubular structure are connected by a contrast-enhancing band of soft tissue (thick notched arrows). Images are displayed in a soft tissue window (window width, 500 Hounsfield units [HU]; window level, 30 HU).
Citation: Journal of the American Veterinary Medical Association 253, 3; 10.2460/javma.253.3.265
Treatment and Outcome
An ovariohysterectomy was performed. Surgery confirmed herniation of the right uterine horn through the left inguinal ring, caudoventral displacement of the right ovary, and stretching of the suspensory ligament of the right ovary. The left uterine horn was grossly normal. The herniated right uterine horn was dilated closest to the uterine body. The dilated segment was continuous with the adjacent narrowed aspect of the uterus. A plaque-like collection of blood was seen on the surface within the dilated portion of the right uterine horn. Uterine tissue samples were submitted for histologic evaluation. The defect in the left inguinal ring was closed. The liver was examined and found to be grossly enlarged and irregularly marginated with a purple and white discoloration. However, no tissues samples of the liver were obtained, because the hepatic mass was deemed nonresectable, and the patient was having anesthetic complications related to decreased blood volume and hypotension that was not responsive to medical management. During surgery, punch biopsies of the mammary masses were performed.
Histologic evaluation of uterine tissue samples revealed cystic endometrial hyperplasia and metritis, with pyometra confined to the right uterine horn. Histologic evaluation of mammary tissue samples revealed mammary gland adenocarcinoma.
The patient recovered from surgery and anesthesia without further complications and was discharged from the hospital 3 days after surgery. The patient did not return for postoperative evaluation of the incision, and the dog was lost to follow-up.
Comments
Mammary neoplasia or herniation of abdominal content was initially suspected in the patient of the present report because of radiographic evidence of round, soft tissue opacity masses in the area of the left mammary chain and inguinal region. However, the definitive cause could not be determined by abdominal radiography alone, warranting further diagnostic imaging.
Ultrasonographic evaluation of the abdomen was instrumental in the detection of the enlarged uterus and the inguinal mass that were of similar echogenicity. On the basis of ultrasonographic findings, pyometra was most likely. Ultrasonography is the diagnostic imaging technique of choice for dogs with suspected pyometra because it provides detailed information about uterine size, uterine thickness, presence of fibrosis or cysts in the endometrium, and the character of uterine fluid.1 Ultrasonographically, cystic endometrial hyperplasia is evident by endometrial thickening with multifocal anechoic dilated cystic glands. However, no cysts were visualized within the uterine walls in the ultrasonographic images of the patient of the present report. The reason for the lack of ultrasonographic changes consistent with cystic endometrial hyperplasia in this patient is unknown. The cysts may have been too small to detect. In the present report, ultrasonographic images were obtained with a 10-MHz transducer. Perhaps the use of a higher-frequency transducer would have allowed for detection of these cystic changes. Fluid accumulation within the uterine lumen is not definitive for pyometra, because both mucometra and hydrometra can result in the same findings. In instances of pyometra, however, leukocyte migration into the uterine fluid results in more echogenic fluid.2 In a routine diagnosis of pyometra, CT is not indicated; however, it was performed in the patient of the present report as part of an unrelated academic research project and was helpful, as it allowed for confirmation of herniation of the uterus through the left inguinal ring.
Inguinal hernias result from a defect in the inguinal ring through which abdominal contents protrude. Content of inguinal hernias may include omentum, fat, ovary, uterus, small intestine, colon, bladder, or spleen. Inguinal hernias may be congenital or acquired; however, acquired inguinal hernias are more common among middle-aged, sexually intact female dogs. Although the exact pathogenesis of inguinal herniation is unknown, evidence suggests that a combination of anatomic, hormonal (specifically estrogens), and metabolic factors contribute to the formation.3,4
Cystic endometrial hyperplasia is an abnormal response of the uterus to chronic or repeated progesterone and estrogen stimulation resulting in an accumulation of fluid within the endometrial glands and uterine lumen. Pyometra may result under these conditions. Dogs with pyometra typically have clinical signs of inappetence, depression, and polydipsia with or without vaginal discharge. The patient is typically afebrile with leukocytosis and prerenal azotemia.5
The patient of the present report did not have a history or clinical signs characteristic of pyometra, which may have been because it was confined to the herniated segment of the right uterine horn. The only clinicopathologic disturbances characteristic of pyometra were a mild neutrophilia and an increase in serum globulin concentration. A low BUN concentration is not typical of a patient with pyometra. In the patient of the present report, the low BUN concentration was likely the result of liver disease, as evidenced by the liver mass identified on CT.
References
1. Hagman R. Canine pyometra: what is new? Reprod Domest Anim 2017;52:288–292.
2. Kinnus J & Nelson N. Cystic endometrial hyperplasia and pyometra. In: Thrall DE, ed. Textbook of veterinary diagnostic radiology. 6th ed. St Louis: Elsevier Saunders, 2013;760–761.
3. Smeak DD. Inguinal hernias. In: Tobias KM, Johnston SA, eds. Veterinary surgery: small animal. St Louis: Elsevier Saunders, 2012;1358–1361.
4. Sontas BH, Toydemir FT, Erdogan Ö, et al. Inguinal herniation with hydrometra/mucometra in a Poodle bitch. Can Vet J 2013;54:840–844.
5. Smith FO. Canine pyometra. Theriogenology 2006;66:610–612.
