A one-year-old, intact female, Maltese dog was presented with a history of anorexia and regurgitation. Thoracic radiographs and ultrasonography scans suggested an abnormal mass in the cranial mediastinal region, and computed tomography confirmed the origin of this mass. Ultrasound-guided fine needle aspiration cytology showed the presence of intermediate to large lymphoid cells showing mitotic figures. B-cell lymphoma was confirmed by the result of a polymerase chain reaction assay for antigen receptor rearrangement, therefore the patient was diagnosed with primary mediastinal large B-cell lymphoma (PMBL). The patient underwent L-CHOP (L-asparaginase, cyclophosphamide, doxorubicin, vincristine, prednisolone)-based chemotherapy, and showed complete tumoral remission from the beginning of chemotherapy. Seventytwo weeks after the completion of chemotherapy, the patient is still alive without any evidence of metastasis or relapse. A standardized treatment protocol has yet to be established for primary mediastinal lymphoma in dogs. This case report describes the complete remission of PMBL by an L-CHOP-based chemotherapy protocol in a young Maltese. Clinicians should consider that L-CHOP based chemotherapy may be useful against PMBL in dogs.

A 2-year-old female Maltese dog was presented with a history of anemia and vaginal hemorrhagic discharge. Physical examination revealed severe vaginal hemorrhagic discharge, abdominal pain, pale mucous membranes, low blood pressure and dehydration. Results of serum biochemistry, hematology, venous blood gas, and electrolyte canine C-reactive protein (CRP) test revealed severe normocytic normochromic anemia, severe neutropenia, a high level of CRP, hypoglycemia, and imbalanced electrolytes. Abdominal ultrasound examination showed focal hypoechoic defect with loss of layering in uterine horn wall. A laparotomy revealed a clear reddish fluid in the abdomen, the fistula of left and right uterine horn, the purulent discharge from fistula, and symptoms of septic peritonitis near by the fistula site. The bitch underwent ovariohysterectomy and recovered without complication. Histopathological diagnosis of the uterine fistula site was adenocarcinoma.

Mitral valvular prolapse (MVP) in dogs is characterized by myxomatous valvular degeneration, which is caused by abnormal valvular thickening and incomplete coaptation of the mitral valve leading to mitral regurgitation. Mitral regurgitation causes left atrial and left ventricular enlargement. Pathogenesis of the disease is unknown, although some studies have suggested the involvement of endothelin and systemic connective tissue diseases. Mitral valvular prolapse in dogs commonly occurs in aged small dog breeds, including Malteses and Shih Zhus. This case study investigated the clinical features of an affected Maltese family and performed pedigree analysis. To the best of the authors’ knowledge, this is the first report of putative familial mitral valve prolapse and regurgitation in Maltese dogs. All family members in this study showed degenerative valvular changes and echocardiographic features of mitral valvular prolapse. Although disease progression differed, all dogs progressed to advanced heart failure stage within 2-3 years after diagnosis. Therefore, this is the first study to identify putative familial mitral valve prolapse in Maltese dogs. This finding suggests strong genetic etiology involved in the development of degenerative mitral valve disease in Maltese dogs. Furthermore, this finding could be a valuable resource for the identification of gene mutations in dogs with familial mitral valvular prolapse.

Male pseudohermaphroditism is not commonly reported in veterinary medicine. Here, a 3-year-old Maltese/poodle mixed dog presented with malformed external genitalia and episodic hematuria. Inspection and palpation of the external genitals showed a malformed penis, shortened prepuce, external urethral orifice, and cryptorchidism. There was no urethral meatus at the tip of the penis. The urethral opening was situated between the prepuce and the penis. The anterior half of the prepuce was absent, and the penis was free and exposed to both trauma and licking. Plain radiographic examination showed absence of an os penis in the penis. A double-contrast cystograph showed the suspected uterus as well as the cystic calculi. A hypoechoic space was seen at the dorsal portion of the urinary bladder. The space was suspected to be the uterus. A sagital ultrasonograph showed cystic calculi in the urinary bladder. During surgery to remove cystic calculi, hypoplastic testes as well as the uterus were observed. Histological examination of the testes showed the seminiferous tubules and interstitial cells. The sertoli cells and spermatogonia were adjacent to the basement membrane. No evidence of spermatogenesis was found. Striated squamous epithelial cells and smooth muscle cells were found in the uterus. This dog had vestigial oviducts as well as a uterus with male-appearing external genitals.