Ambiguous genitalia in a fertile, unilaterally cryptorchid male miniature schnauzer dog

Case report: Persistent Müllerian duct syndrome and enlarged prostatic utricle in a male dog

A 1-year-old male intact Miniature Schnauzer mix was presented for chronic intermittent hematuria. Abdominal ultrasonography revealed a large, fluid-filled cystic structure extending cranially and dorsally to the prostate. Computed tomography scan images revealed that the fluid-filled cavity resembled a uterus, with both horns entering the scrotum through the inguinal canal adjacent to the testes. On cytogenetic analysis, the dog was found to have a homozygote mutation on AMHRII consistent with persistent Müllerian duct syndrome (PMDS). A gonadohysterectomy was performed, and surgical and histologic findings confirmed the presence of a uterus, oviducts, vagina, and testes in this dog. Additionally, an intraoperative fluoroscopy exam revealed a communication between the uterus and the bladder via an enlarged utricle, explaining the hematuria and urine in the reproductive tract (urometra). To our knowledge, this is the first clinical report of a phenotypically intact male dog with PMDS and urometra due to an enlarged prostatic utricle. This case illustrates a combination of a disorder of sex and urogenital sinus development.

Persistent Mullerian duct Syndrome in a Brazilian miniature schnauzer dog

Here we describe an eight-year-old miniature schnauzer (MS) dog from Brazil with Persistent Mullerian Duct Syndrome (PMDS) and the single base pair substitution in AMHR2 exon 3, first detected in this breed in the USA. This finding is evidence of mutation dissemination to South America. In PMDS, a type of XY Disorder of Sex Development (DSD), dogs with a male karyotype and external phenotype also have a uterus, oviducts, and a cranial vagina internally. Approximately half of PMDS MS are unilaterally or bilaterally cryptorchid and many develop pyometra and/or Sertoli cell tumor. Bilateral Sertoli cell testicular tumors were present in this case, and the dog died a few days after surgical castration and hysterectomy. Although the karyotype was compatible with male chromosomal sex, a Robertsonian translocation was also identified, which may be an incidental finding. This report emphasizes the importance of cytogenetic and molecular genetic analyses, along with clinical examination, to identify chromosomal or genetic variations associated with canine PMDS. These are helpful tools to obtain early diagnosis in the MS, which is important to improve health outcomes for affected dogs and to reduce the prevalence of PMDS and cryptorchidism in this breed by avoiding the mating of carriers.

Canine cryptorchidism: An update

This review article is aimed at providing an update on canine cryptorchidism based on the research studies published in this area over the last 26 years. Although a majority of these research studies were directed at investigating the genetic and molecular basis of cryptorchidism, the mechanisms underlying this problem in dogs are still not clear. Future studies using advanced genomic and molecular approaches and including a larger number of dogs of multiple breeds are required to further our understanding of canine cryptorchidism. Diagnosis and treatment of cryptorchidism in dogs have not received much attention. Research advancements include investigation of ultrasonography and anti-Müllerian hormone assay as potential diagnostic methods. Advancements in treatment include the use of laparoscopic-assisted cryptorchidectomy. Based on the available literature, this method appears to be the best for removal of abdominal cryptorchid testes from dogs. However, future studies that compare laparoscopic-assisted cryptorchidectomy with the traditional approaches are required for a more conclusive determination of the best method for cryptorchidectomy in dogs.

Gonadal and sex differentiation abnormalities of dogs and cats

The molecular steps in normal sexual development were largely discovered by studying patients and animal models with disorders of sexual development (DSD). Although several types of DSD have been reported in the cat and dog, which are often strikingly similar to human DSD, these have been infrequently utilized to contribute to our knowledge of mammalian sexual development. Canine and feline cases of DSD with sufficient evidence to be considered as potential models are summarized in this report. The consensus DSD terminology, and reference to previous terminology, is used to foster adoption of a common nomenclature that will facilitate communication and collaboration between veterinarians, physicians, and researchers. To efficiently utilize these unique resources as molecular tools continue to improve, it will be helpful to deposit samples from valuable cases into repositories where they are available to contribute to our understanding of sexual development, and thus improve human and animal health.