and Relevance: Here, we report atypical clinicopathological features observed in the case of CEL. These findings have potential biological, diagnostic, and prognostic relevance, emphasizing the need for further studies to elucidate their clinical significance and to expand the understanding of this disease.

An adult castrated male dog was presented with persistent hematochezia. Digital rectal examination and endoscopy found multiple colorectal masses. Complete blood count and serum biochemical results were within the reference interval. Fine needle aspirate of the masses indicated a diagnosis of inflamed polyps with a primary differential of malignancy. Histopathologic examination using endoscopy-guided incisional biopsy of the masses revealed an inflamed neoplasm with ossification. A colectomy was performed to remove the tumor. Subsequent histopathologic examination of the surgically resected masses resulted in a diagnosis of colorectal carcinoma in situ (CiS) with immune infiltrates, which were subject to immunohistochemical and flow cytometric immunophenotyping. The immunohistochemistry confirmed intraepithelial CD3 + T cells within CiS. The flow cytometric analysis indicated tumor-infiltrating CD4 + T, CD8 + T, and CD11b + myeloid subsets. The flow cytometric analysis of circulating and tumor-infiltrating leukocytes demonstrated a preferential expansion of CD25 + FOXP3 + regulatory T cells within CiS. To the author’s knowledge, this is the first report to show clinical evidence emphasizing the immunogenicity and immune-suppressive environment of canine colorectal CiS. Our case will be valuable in providing a rationale for basic research that dissects the immune environment for canine colorectal cancers for the future development of cancer immunotherapy.

An adult female dog was presented for evaluation of rapid growth of mammary gland masses. Complete blood count, serum biochemistry, and diagnostic imaging results were unremarkable. Fine needle aspirates of the mammary masses indicated mammary carcinoma characterized by large globoid cells with finely granular eosinophilic globules or Melamed-Wolinska-like bodies. A regional mastectomy was performed on the masses. Subsequent histopathologic examination of the surgically resected masses resulted in a diagnosis of mammary comedocarcinoma with nodal metastasis and distinct perivascular immune infiltrates, which were subject to immunohistochemical and flow cytometric immunophenotyping. Immunohistochemical examination confirmed the infiltration of CD3 + T and PAX5 + B lymphocytes. Flow cytometric analysis demonstrated tumor-infiltrating CD4 + CD25 + FOXP3 + regulatory T, CD8 + T, CD11b + myeloid, and CD21 + B cells. Of note, paired flow cytometric analysis of peripheral blood and tumor tissues showed a preferential tumor infiltration of regulatory T and B cells. Approximately two months after the mastectomy, the tumor reoccurred at the surgery site. The dog died due to deteriorating conditions. We report a rare case of canine mammary comedocarcinoma, providing clinical, clinicopathologic, histologic, and immunophenotypic characteristics. Our case is valuable in providing a rationale for basic research that maps the immune landscape of mammary comedocarcinoma to identify key immune subsets for cancer progression.

A 6-year-old spayed female French Bulldog presented with a left-sided chest wall tumor. Physical examination revealed that the tumor was firmly adhered to the chest wall. A preoperative punch biopsy of the tumor revealed a grade 2 soft tissue sarcoma (STS). On computed tomography, the tumor’s dimensions were assessed as 6.5 × 5.7 × 3.5 cm, and it exhibited invasiveness near the tissue surrounding the ninth rib. The tumor size was large in comparison to the dog’s chest wall area. Hence, if the traditional wide-margin resection surgery were to be performed, primary wound closure seemed impractical and could potentially result in respiratory function complications. Therefore, considering the extent of tumor invasion and grade, deep margins were established to include the removal of the eighth to tenth ribs, and a 1-cm lateral margin was designated to enable primary wound closure. To reconstruct the chest wall, polypropylene mesh was attached to the adjacent ribs and the remaining muscles were sutured and covered over the mesh. The dog exhibited a rapid recovery beginning the day after the operation. Postoperative biopsy confirmed that the tumor was a grade 2 STS, and the surgical margins were evaluated as incomplete. The owner chose to pursue follow-up observation instead of chemotherapy. In this study, the surgical approach was chosen based on the importance of functional recovery after surgery. Recent research indicates that the tumor grade is more critical for postoperative prognosis than the extent of surgical margins when removing an STS.

An adult male dog was presented for hemorrhagic pericardial effusion. Echocardiography and computed tomography revealed nodule-like lesions on the pericardium. Cytology of pericardial effusion and excisional pericardial lesions indicated neoplastic effusion. Histopathology indicated an inflamed neoplasm with a primary differential diagnosis of hemangiosarcoma and malignant mesothelioma (MM). Immunohistochemistry showed that atypical cells were positive for cytokeratin and vimentin, but negative for CD31, strongly favoring pericardial MM. Postoperative NT-proBNP level remained increased, which led to the administration of epirubicin to minimize potential cardiotoxicity. During the 4 cycles of epirubicin treatment, a total cumulative dose of 108 mg/m ² was administrated and no effusion recurrence was observed. After a month post-completion of chemotherapy, however, pleural effusion was detected with cardiac masses. The owner requested no further diagnostic investigations and chemotherapy. Due to deteriorating conditions, the dog died 132 days after the first presentation. Our case is the first notable attempt to treat canine malignant mesothelioma with epirubicin, providing the clinicopathologic, diagnostic routine, and clinical course of the affected dog.

Traumatic reticuloperitonitis (TRP) often referred to as hardware disease is a common disease of cattle, which is considered the most frequent cause of anterior abdominal pain in cattle. The incidence of TRP has decreased significantly, but the diagnosis and treatment of TRP are still clinically significant because of its economic impact. An eight-year-old female Mongolian cow weighing 400 kg, was presented to the Korean (College of Veterinary Medicine, Jeju National University)–Mongolian (School of Veterinary Medicine, Mongolian University of Life Science) volunteer team (KMVT) with the primary complaints of depression and anorexia during their outreach activity for veterinary volunteer service in the field of the suburban farm of Mongolia. TRP was diagnosed based on the clinical symptoms, auscultation, and back grip test results. An emergency rumenotomy was performed with the consent of the owner. The patient was anesthetized using distal paravertebral anesthesia and the inverted L block method while a makeshift restraint frame was constructed on-site. The rumenotomy was performed to explore the rumen and reticulum. Foreign bodies were identified and removed. The surgery was performed successfully. The patient’s recovery after the surgery was normal, and the appetite was restored. This paper describes a case of TRP in a Mongolian cow, including the diagnosis, surgical preparation, and surgery successfully performed in the field of suburban farm of Mongolia in detail.