Sry-negative XX sex reversal in a family of Norwegian Elkhounds

Two related female Norwegian Elkhounds were evaluated at 6 and 8 months of age for enlarged clitori. Both had a 78 XX karyotype. Histology of their internal reproductive tracts demonstrated 1 to be an XX true hermaphrodite with bilateral ovotestes and the other to be an XX male with bilateral aspermatogenic testes. Polymerase chain reaction-based tests of genomic DNA showed that both dogs lacked Sry, the testis-determining gene. Pedigree analysis was consistent with an autosomal recessive mode of inheritance, as has been reported in the American Cocker Spaniel and the German Shorthaired Pointer. This is the 1st reported case of familial Sry-negative XX sex reversal in the Norwegian Elkhound. A summary of 34 previously unreported cases of dogs with masculinized external genitalia and a normal 78 XX karyotype seen from 1980 to 1997 is given.     

Choledocholithotripsy in a mare

Obstructive choledocholithiasis in a 12-year-old mare was corrected surgically by choledocholithotripsy. The mare had a history of chronic weight loss, intermittent fever, partial anorexia, jaundice, recurrent abdominal pain, and an abdominal mass palpable per rectum. Values for alkaline phosphatase, bilirubin, gamma-glutamyl transferase, sorbitol dehydrogenase, and bromsulpthalein half-life were increased and bilirubinuria was evident before surgery. Two liver biopsies revealed periportal and portal fibrosis, bile duct proliferation, cholestasis, and variable amounts of hepatocellular necrosis, with infiltration by polymorphonuclear cells. Immediate clinical improvement was seen after surgery, and results of selected liver function tests gradually returned to normal. Since surgery, the mare has returned to her normal weight, has remained clinically normal for liver disease for 28 months, and has been useful as a broodmare.     

Thecoma in a mare

A 4-year-old crossbred Thoroughbred mare was referred to the University of Tehran Veterinary Medical Teaching Hospital for evaluation of a mass in the pelvic cavity. The mare had been partially anorectic and pyrexic. On clinical examination, the mare was thin and depressed, with body temperature of 38°C, a pulse rate of 38 beats/minute, and a respiratory rate of 10 breaths/minute. Palpation per rectum revealed a large, smooth and tense mass in the anterior part of the pelvic cavity. Ultrasound examination confirmed the presence of a soft tissue mass with a thick wall. The inner surface of the mass had a villous-like appearance. The stroma of the mass was mottled, with accumulation of speckled and hypoechoic to slightly hyperechoic fluid. Hormone assays revealed low serum concentration of testosterone. Serum progesterone concentration indicated that active luteal tissue and serum estradiol concentration was 24 pg/ml. On histological examination, the sections from the tumor were composed of oval- or spindle-shaped cells loosely arranged in diffuse sheets or irregularly interlacing fascicles. On the basis of these histological findings, the large tumor mass of the left ovary was considered to be a thecoma. To our knowledge, the details of the clinical, ultrasonographic, endocrinologic, and histologic findings of this tumor in the mare have not been described in the veterinary literature.     

Presumptive Sry-negative XX sex reversal in a llama with multiple congenital anomalies.

Multiple congenital abnormalities of the external genitalia consistent with XX sex reversal were detected in a juvenile llama. The llama had a typical female karyotype (74, XX) and did not have a Y chromosome, but a minute chromosome was detected. To determine whether a piece of Y chromosome containing the Sry gene might be located in a small translocation, DNA analysis by polymerase chain reaction was performed; the Sry gene was not detected. Histologic examination revealed ovarian tissue, whereas testicular tissue was not found. External genitalia were partially masculinized, indicating that the urogenital sinus, genital tubercle, and genital swellings had been exposed to androgens during development, although the dam had not received exogenous androgens. Testicular tissue in the ovaries may have been undetected or had regressed prior to birth, as has been reported in sex reversal in mice.     

Vestibulovaginal leiomyosarcoma in a mare

A 14-year-old Quarter Horse mare presented for a mass within the vestibule and vagina resulting in external compression and incomplete occlusion at the external urethral opening with subsequent difficulty urinating. Examination revealed an approximately 15 × 10 cm lobulated mass within the vestibule and caudal vagina attached via a broad base dorsally. Histopathology of the mass identified a low-grade leiomyosarcoma. Complete resection was not possible, and surgical debulking of the mass was performed during standing sedation using a vessel-sealing and dividing device. The mare was discharged 3 days post-operatively without any complications. Recheck examinations performed at 1 month and 8 months’ post-surgery revealed excellent healing of the surgical site and no apparent tumour regrowth.     

Shivering in a thoroughbred mare

An 11-year-old mare presented with neuromuscular deficits and what resembled shivering in the left hind limb. On necropsy, there was no evidence of denervation atrophy of the left hind gastrocnemius muscle. The spinal cord had a small, right-sided lesion at C3-C4 and C4-C5. Tests for equine herpesvirus-1 and Sarcocystis spp. were negative.     

Pneumonia in a Paso-Fino mare

A 5-year-old Paso-Fino mare was presented for severe respiratory distress. The mare had foaled 2 months prior to presentation. The horse was in poor body condition with a dull hair coat. A mild fever was noted during physical examination and increased bronchovesicular sounds were auscultated. Thoracic radiographs showed an interstitial pattern and an alveolar infiltrate with distinct air bronchograms. Moderate purulent inflammation with increased mucus was observed in tracheal wash fluid, but no infectious agents were identified. A bronchoalveolar lavage (BAL) contained a large amount of mucus and reactive mononuclear phagocytes with variable numbers of intracellular fungal organisms morphologically consistent with Pneumocystis carinii. The mare had undetectable levels of immunoglobulin M (IgM) and decreased IgG levels in the serum. Immunophenotyping revealed decreased expression of major histocompatability complex (MHC) class II molecules. Moderate to marked hyperplasia of type II epithelial cells was present throughout histologic sections of lung, but the fungal organisms were not observed. A culture system has not been developed for diagnosis of P carinii infection. Instead, diagnosis of P carinii pneumonia is achieved by microscopic identification of characteristic morphologic features of the pathogen. Cytologic examination of BAL fluid is the preferred method used to diagnose human infection with P carinii. In humans, the diagnostic sensitivity of cytology is significantly higher than the sensitivity of histopathologic examination of lung biopsies. The difference in sensitivity between BAL cytology and lung histopathology may also apply to the diagnosis of P carinii pneumonia in horses. (MacNeill AL, Alleman AR, Franklin RP, Long M, Giguère S, Uhl E, López-Martinez A, Wilkerson M. Pneumonia in a Paso-Fino mare [ Pneumocystis carinii pneumonia].     

Arrhenoblastoma in a mare.

An ovarian neoplasm measuring 10 by 8 by 6 cm was surgically removed from a 14-year-old Appaloosa mare. For 2 years prior to surgery, the mare had manifested marked behavioral changes, becoming aggressive toward other broodmares. Histologically, the tumor was found to be an arrhenoblastoma. Preoperative endocrinologic findings (high serum testosterone and low serum estradiol concentrations) supported the diagnosis.     

Uterine rupture in a mare

This report involves uterine rupture in a mare, which was unique because it was not associated with assisted or difficult foaling. We describe an alternative to surgical correction of the condition and illustrate the need for luminal uterine palpation, so that uterine rupture does not go undiagnosed.     

Uterine hematoma in a mare

An 8-year-old grey Arabian mare was presented for reproductive evaluation with a history of failing to become pregnant during two previous breeding seasons. An enlargement was identified on the right uterine horn on rectal examination which was confirmed as a fluid-filled nonechogenic mass on ultrasonography. Subsequent examination procedures and laparotomy revealed an old hematoma in the wall of the uterine horn.