Objective The objective of this study was to describe the clinical features, prognostic factors, and outcomes in dogs with surgically treated salivary gland carcinoma. Study design Multi‐institutional retrospective case series. Animals Seventy‐two client‐owned dogs from 16 institutions with surgically excised salivary gland carcinoma. Methods Medical records of dogs undergoing sialoadenectomy from January 1, 2000 to January 1, 2020 were reviewed for signalment, clinical signs, preoperative staging results, preoperative mass evaluation, complications, histopathologic diagnosis, local recurrence, metastatic disease, and survival times. Survival functions were estimated using the Kaplan‐Meier estimator. Factors related to survival were individually tested using the log‐rank test. Results The overall median survival time (MST) associated with salivary carcinoma was 1886 days. Local recurrence occurred in 29/69 (42%) dogs with an overall disease‐free interval (DFI) of 191 days. Metastatic disease occurred in 22/69 (31.9%) dogs, with an overall DFI of 299 days. Lymph node metastasis was present at the time of surgery in 11/38 (28.9%) dogs in which lymphadenectomy was performed at the time of surgery; these dogs had a shorter DFI at 98 days (P = .03) and MST at 248 days (P < .001). Conclusion The prognosis for dogs with salivary gland carcinoma treated surgically was more favorable than previously reported. Nodal metastasis was a negative prognostic factor for canine salivary gland carcinoma. Clinical significance Surgical intervention should be considered for dogs with salivary carcinoma.

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Background Feline indolent cutaneous T‐cell lymphoma (ICL) is an uncommon neoplastic disease. There is currently no consensus on treatment recommendations for ICL. Objective To report the clinical outcome of three cats with ICL treated with hypofractionated electron‐beam radiotherapy (RT). Animals Three privately owned cats with ICL. Materials and methods Medical records and client surveys were reviewed. A diagnosis of probable ICL was based on history, clinical presentation and histopathological findings, and confirmed using CD3 immunohistochemical analysis and PCR for antigen receptor gene rearrangement (PARR). All cats were treated with hypofractionated RT (four fractions of 8 Gy). Results All cats presented with skin lesions characterised by erythema and alopecia that were refractory to previous treatment with systemic glucocorticoids. Before hypofractionated RT treatment, lesions were histologically described as having diffuse infiltration of the dermis with CD3+ T cells. Molecular clonality analysis revealed clonal T‐cell receptor gamma gene rearrangement. After RT, two cats showed histological improvement defined by decreased infiltration of lymphocytes, with cellular infiltrate present only in the deeper dermis; one cat had near complete histological resolution of lesions with only minimal residual lymphocytes. One cat was determined to have a complete clinical response while the other showed partial responses. No acute adverse effects of radiation were observed; chronic effects included leukotrichia, partial alopecia and mild fibrosis. All clients reported improvement in quality of life for their cats. Conclusions and clinical importance Clinical and histological improvement in these cats suggests that hypofractionated RT can be a useful treatment modality for cats with ICL

Background: Clonal hematopoiesis of indeterminate potential (CHIP) is a clinical entity of aging humans that is characterized by cancer-associated mutations in white blood cells, without evidence of overt neoplasia. CHIP has been associated with an increased risk of hematologic cancers, cardiovascular disease, and all-cause mortality. We hypothesized that somatic mutations in specific genes associated with human CHIP would be detectable in the blood of aged dogs not known to have hematologic disorders. Methods: DNA from paired germline and whole blood samples from 93 geriatric canine patients affected by solid cancer were subjected to targeted next generation sequencing. Impact of the variants was predicted using Polymorphism Phenotyping version 2 software (PolyPhen-2, Harvard). Clinical and demographic data were extracted from medical records. Results: Somatic variants were detected in peripheral blood of four (4.3%) female dogs aged 12-15 years. Affected genes were ASXL1, KIT, SF3B1, TET2, RUNX1, and PPM1D. The variant in PPM1D was a nonsense mutation, while the other five variants were single nucleotide non-synonymous variants in protein coding regions of the genes. Following analysis by PolyPhen-2, the single nucleotide variants in KIT and SF3B1 were predicted to be benign, while the variants in ASXL1, TET2, and RUNX1 were predicted to be damaging. Conclusion: These results support the presence of variants in CHIP-associated genes in geriatric canids at a frequency similar to that observed in people, and the dog represents the first species in which the genetic lesion of CHIP has been documented. Further investigations are needed to confirm the association of this genetic lesion with clinical outcomes. Citation Format: Kimberley N. Sebastian, Hatice Gülçin Özer, Cory Howard, Laura Chadsey, Arletta Lozanski, Tzyy-Jye Doong, Gerard Lozanski, Wenjuan Ma, William C. Kisseberth, John C. Byrd, Bonnie K. Harrington. Clonal hematopoiesis of indeterminate potential in the companion dog [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1620.

A 12 yr old spayed female mixed-breed dog presented for evaluation of a recurrent soft-tissue sarcoma. On physical examination, a firm mass was palpated ventral to the left ramus of the mandible. A fine-needle aspirate of the mass was suggestive of a round-cell neoplasm. A complete blood count, serum biochemical profile, and an abdominal ultrasound with liver and splenic aspirates were performed, and no clinically relevant abnormalities were identified. Advanced imaging of the skull identified an enlarged parotid salivary gland and an enlarged ipsilateral medial retropharyngeal lymph node. The medial retropharyngeal lymph node was sampled via fine-needle aspiration, and a round-cell population similar to what was present in the mass was identified. An incisional biopsy was performed under general anesthesia, which yielded a diagnosis of salivary gland extramedullary plasmacytoma, confirmed with immunohistochemistry (MUM-1). The parotid salivary gland and medial retropharyngeal lymph node were then surgically excised, and metastasis to the lymph node was confirmed by histopathology. The dog remained alive for 685 days after surgery until she was euthanized for hindlimb paresis of undetermined cause.