Müller´s Duct Persistence Syndrome Associated with Cryptorchidism, Sertoli Cell Tumor and Pyometra in a Miniature Schnauzer
Authors: Zambarda Tais Teixeira , Stefani Renata Queiroz , Sonne Luciana , Pöppl Álan Gomes 
Published: March 2020

Background: Sexual development disturbances (SDD) are divided in SDD with XX genotype (SDD XX) and SDD with XY genotype (SDD XY). Among SDD XY, the Müller´s duct persistence syndrome (MDPS) is characterized by XY karyotype individuals with male external genitals; however, with internal female reproductive organs such as uterine horns, uterus, and cranial vagina portion. The MDPS cases and their related complications are considered very rare in veterinary medicine. The aim of the present case report is to describe the clinical and pathological aspects of a MDPS case associated with cryptorchidism, Sertoli cell tumor, and pyometra in a Miniature Schnauzer dog.Case: A 7-year-old male Miniature Schnauzer weighting 7 kg was brought to veterinary consultation due to owner´s complain of frequent vomiting, apathy, abdominal algia and progressive scrotal enlargement in the last two months. Physical exam reveals hyperthermia (39.7°C), discrete dehydration, enlarged popliteal lymph nodes as well as scrotum enlargement with only one palpable testicle. A blood sample collected for complete blood count showed regenerative anemia, thrombocytopenia, and neutrophilia with left shift in the leukogram. Abdominal ultrasound examination indicated the presence of a tubular structure filled by anechoic content extending from the scrotum to caudal abdomen. Moreover, a 6.39 x 8.54 cm heterogeneous mass in the medial mesogastric region became evident. The patient was hospitalized and submitted to exploratory laparotomy after 24 h due to rectal temperature increase (41°C), worsened abdominal pain and intense apathy. There was free purulent liquid in abdominal cavity and two uterine horns were documented. The left uterine horn passes through inguinal ring and both horns were filled by purulent material. At the right uterine horn extremity there was the mass previously document at ultrasound. The structures were removed and sent to histopathological examination. The microscopic exam confirmed testicular and uterine tissue; furthermore, a Sertoli cell tumor and pyometra were also characterized. The dog was kept at the hospital receiving fluid, antibiotics, analgesics, and anti-inflammatory therapy. After five days the animal was discharged with clear clinical recover. A sample for karyotyping was collected from the oral mucosa which reveals a XY karyotype in the dog. By this way it was concluded that the dog suffers from a SDD XY with MDPS associated to cryptorchidism, Sertoli cell tumor and pyometra.  Discussion: The MDPS cases are often associated with cryptorchidism and testicular tumors. Miniature Schnauzers is one of the most affected dog breeds with this condition, and the heritability pattern is already described. Most cases are identified in adult to old-aged dogs after vague clinical signs investigation such as apathy, anorexia and abdominal or inguinal enlargement, as observed in the present report. When Sertoli cell tumor are present, the hormone secretion pattern of this neoplasia may influence complications occurrence. Once higher estrogen levels may induce endometrial gland proliferation, hydrometra and pyometra are among these complications, as well as reduced hematopoiesis. Moreover, progesterone levels could be also increased favoring pyometra pathophysiology. By conclusion, despite very rare, MDPS should be investigated in Miniature Schnauzers with vague clinical signs, especially cryptorchidic ones. Karyotyping and histopathology were crucial to confirm the diagnosis. Moreover, no other case with MDPS, cryptorchidism, Sertoli cell tumor, and pyometra was found in the published literature consulted.