Search Results (41)

Studies worldwide report cutaneous neoplasms in dogs; however, data in the arid regions of Mexico remain scarce. Here we report the main malignant cutaneous neoplasms diagnosed by fine needle aspiration cytology (FNAC), and describe the associations with age, sex and breed in Mexicali. Neoplastic lesions accounted for 25.52% (698/2735) of the cases, of which 56.59% (395/698) were malignant. The highest prevalence was observed in dogs aged 9–12 years (n = 193), intact males (n = 162), and mixed-breed dogs (n = 247). Round cell neoplasms (n = 309), including lymphoma, transmissible venereal tumors (TVT), and mast cell tumors (MCT), were the most common cell lineage. Using dogs aged 0–4 years as the reference group, dogs aged 9–12 years had 0.241 times the odds of developing malignant neoplasms (95% CI: 0.141–0.415, p = 0.0025). Using neutered males as the reference group, intact females showed 2.499 times the odds of developing malignant neoplasms (95% CI: 1.462–4.271, p = 0.0042). Compared to mixed-breed dogs, Schnauzers (OR = 0.161) showed significantly lower odds of malignancy (95% CI: 0.082–0.317, p = 0.0004), while Pitbull Terriers had 1.748 times more chance of present malignant neoplasia (95% CI: 1.014–3.013, p < 0.0001). This study provides significant epidemiological evidence on canine cutaneous neoplasms in an arid region of Mexico, identifying key risk factors and distribution patterns that can guide preventive, diagnostic, and therapeutic strategies tailored to regional characteristics. Full article

Cutaneous neoplasia is among the most common illnesses in dogs and can pose significant risks. Accurate morphological diagnosis of these conditions is vital for effective treatment and management. In this retrospective study, a total of 3746 canine skin biopsies were submitted to a veterinary reference diagnostic laboratory and evaluated using histopathology. The variables assessed included age, sex, breed, lesion, location, and histopathological diagnosis. Non-neoplastic lesions accounted for 61% of all analyzed samples, while neoplastic tumors accounted for 39%. When looking at age, dogs ranging 3–6 years and 7–9 years had at least six times higher risk of developing malignant neoplasia compared to those aged 0–2 years. Among the malignant neoplasms, mast cell tumors, hemangiosarcoma, and squamous cell carcinoma were the most observed, representing 30%, 18%, and 12% of cases, respectively. The breeds most frequently affected by malignant neoplasms included Pit Bull Terriers, Boxers, and mixed breeds, all of which comprised the majority of mast cell tumor cases at 50.54%. These findings are novel in this field and may assist small animal veterinarians in making preliminary diagnoses, while also helping pet owners understand the importance of skin cancer and its early detection. Full article

Background/Objectives: Mast cell tumors (MCTs) are the second most common malignant neoplasms in dogs. Histopathological grading and clinical staging are the main tools for estimating biological behavior and disease extent; thus, both are essential for therapeutic decision-making and prognostication. However, the biological behavior of MCTs in dogs is variable, and it sometimes deviates from expectations. In a previous study, we identified 12 transcripts whose expression profile allowed a clear distinction between Kiupel low-grade and high-grade cutaneous MCTs (cMCTs) and was associated with prognosis. Building on these findings, this study evaluated the predictive potential of these transcripts’ expression profiles in classifying cMCTs into low-grade and high-grade. Methods: A logistic regression classifier based on the expression profiles of the identified transcripts and able to classify cMCTs as low- or high-grade was developed and subsequently tested on a novel dataset of 50 cMCTs whose expression profiles have been determined in this study through qPCR. Results: The developed logistic regression classifier reaches an accuracy of 67% and an area under the receiver operating characteristic curve (AUC) of 0.76. Interestingly, the molecular classification clearly identifies stage-IV disease (90% true positive rate). Conclusions: qPCR analysis of these biomarkers combined with the machine learning-based classifier might serve as a tool to support cMCT clinical management at diagnosis. Full article

Vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis and has been identified as an autocrine growth factor for neoplastic cells of several tumors. The aim of this study was to evaluate VEGF expression in canine mast cell tumors and their respective lymph node metastases. For this purpose, 28 patients with mast cell tumors and confirmed regional lymph node metastasis were selected. The samples were submitted for analysis with immunohistochemistry. VEGF was expressed in 14/28 patients (50%) and 35.7% of primary MCTs (10/28), and only 14.3% expressed VEGF in both the primary tumor and its respective metastasis (4/28), with fair agreement (Κ = 0.250). There was a weak correlation between VEGF and tumor size (p = 0.016, rs = 0.045). In this cohort, survival time was correlated with Kiupel grade, mitotic index, tumor necrosis, tumor location, and systemic treatment. VEGF immunolabeling had no influence on survival; however, patients with positive expression may benefit from specific therapy. Full article

Mast cell tumors (MCTs) are common skin neoplasms in dogs. Prognostic indicators include histologic grade, clinical stage, high Ki-67 index, elevated argyrophilic nucleolus organizer regions (AgNOR) index, c-kit mutations, and recurrence after surgery. Blood serum redox status has been shown to correlate with prognostic factors in canine lymphoma and mammary tumors. This study aimed to assess the correlation between established prognostic factors and serum redox status and lipid metabolism analytes in dogs with MCTs. Dogs with cutaneous (n = 33) or subcutaneous (n = 6) MCTs, without comorbidities, were studied. Staging was evaluated based on cytology of regional lymph nodes and ultrasound-guided liver and spleen aspiration cytology. Histologic grading and immunohistochemical staining for Ki-67 and KIT patterns were performed on excised tumor specimens. Dogs were categorized by Patnaik grading (1–3), Kiupel grading (low/high), metastatic status, Ki-67 positive nuclei per cm² (>23 or ≤23), and KIT pattern (I, II–III). Paraoxonase-1, Butyrylcholinesterase, Cupric Reducing Antioxidant Capacity (CUPRAC), Diacron Reactive Oxygen Metabolites (d-ROMs), and oxy-adsorbent levels were measured before any therapeutic intervention. ANOVA and independent t-tests were used to detect differences in the mean values among groups. Paraoxonase-1 activity was significantly lower in Patnaik grade 3 (p = 0.003) and Kiupel high-grade (p = 0.022) MCTs. No significant differences were found in CUPRAC, d-ROMs, or oxy-adsorbent levels across different prognostic groups. This study found a significant correlation between histologic grading and Paraoxonase-1 activity, suggesting a potential role of Paraoxonase-1 as a prognostic biomarker in canine MCTs. Full article

Canine mast cell tumors (MCTs) are common skin neoplasms with varying biological behaviors. The KIT proto-oncogene plays a key role in the development of these tumors, and internal tandem duplications on exon 11 are usually associated with more aggressive behavior, increased local recurrence, and decreased survival time. However, apart from exons 8–11 and 17, there is limited understanding of the overall KIT mutational landscape in canine MCTs. This work aims to analyze the entire KIT coding sequence (21 exons) in a cohort of 62 MCTs, which included 38 cutaneous and 24 subcutaneous tumors, and potentially identify new variants. In addition to confirming previously reported activating KIT mutations in exons 8, 9, and 11, we identified new variants in exons 2, 3, 5, 16, and the 3′ untranslated region (UTR). Notably, these last variants include an amino acid change (Asp/His) in exon 16. Additionally, we confirmed a differential prevalence of KIT variants in cutaneous and subcutaneous MCTs. These findings enhance our understanding of the KIT proto-oncogene coding sequence and provide valuable information for future confirmatory studies. Full article

A cutaneous mast cell tumor (cMCT) is among the most common tumors in dogs. Endocannabinoids (eCBs) belong to the endocannabinoid system (ECS), which involves also cannabinoid receptors and an enzymatic system of biosynthesis and degradation. In this study, plasma levels of N-arachidonoylethanolamine (AEA), 2-arachidonoylglycerol (2-AG), N-palmitoylethanolamine (PEA), and N-oleoylethanolamine (OEA) were evaluated in 17 dogs with MCTs of varying histological grades and clinical stages, as well as in a control group of 11 dogs. Dogs affected by cMCT had higher plasma levels of 2-AG (p = 0.0001) and lower levels of AEA (p = 0.0012) and PEA (p = 0.0075) compared to the control group, while no differences were observed at the OEA level between healthy and cMCT dogs (p = 0.9264). The ability of eCBs to help discriminate between healthy and cMCT dogs was interrogated through the area under the ROC curve (AUC). An accuracy of 0.98 (95% confidence interval [CI], 0.94–1.02) was found for 2-AG, of 0.85 (95% CI, 0.71–0.99) for AEA, and of 0.81% for PEA (95% CI, 0.64–0.69). Values > 52.75 pmol/mL for 2-AG showed 94% sensitivity and 90% specificity in distinguishing cMCT. This is the first study to demonstrate alterations in plasmatic levels of eCBs in dogs affected by MCTs, suggesting the significance of these biomarkers in the tumorigenic process and their potential use as biomarkers in the future. Full article

Several reports have indicated that canine MCTs express a mutated form of a tyrosine kinase receptor, namely KIT, that is involved in abnormal mast cell growth and differentiation. Currently, the post-surgical prognosis for MCTs is related to three different KIT immunohistochemical expression patterns. However, to our knowledge, there are few studies specifically exploring the efficacy of treatment with tyrosine kinase inhibitors related to KIT staining pattern. The purpose of this study was to investigate the potential theragnostic role of KIT expression patterns by studying their correlation to the overall survival and progression-free survival in dogs treated with only tyrosine kinase inhibitors immediately after surgery. We selected 66 cases of canine cutaneous MCTs with complete clinical background. A statistical analysis was performed to assess the overall survival status. Our data suggest an important role of KIT in the etiopathogenesis of canine MCTs and indicate that the anomalous cytoplasmatic distribution of KIT is potentially related to a lower efficacy of tyrosine kinase inhibitors, thus providing a significant prognostic information about the treatment outcome. Full article

Cancer is the most common cause of death in adult dogs. All dogs would benefit from early diagnosis, but there are no specific guidelines regarding the schedule of cancer screening in companion animals. The aim of this study was to retrospectively evaluate the age at diagnosis in Italian oncological canine patients. A total of 14,636 canine histologically confirmed neoplastic cases were coded according to the Vet-ICD-O-canine-1 and stratified by malignancy, sex, neutering status, breed, cephalic index, body size, and tumor type. Differences in age distribution were analyzed and the influence of these variables on the time of first malignancy diagnosis was assessed using an event history analysis model. The median age at diagnosis for benign and malignant tumors was 9 and 10 years, respectively. Intact and purebred dogs were diagnosed earlier, but the median age differed significantly by breed. The earliest age at diagnosis was recorded for lymphomas and mast cell tumors. The model showed an accelerating effect of large size, brachy- and dolichocephaly, and sexual integrity in female dogs on the time of malignancy diagnosis. Our results confirm that a “one-size-fits-all” approach to cancer screening is not accurate in dogs and provide relevant data that may lead to the establishment of breed-based screening schedules. Full article

Toceranib phosphate (toceranib) is approved for canine mast cell tumor treatment. However, no long-term response to toceranib in canine HSTCL has been reported. Here, we describe a case of a 10-year-old castrated mixed-breed dog that presented with a 3-month history of weight loss, polydipsia, and polyuria. The clinicopathological and imaging abnormalities included icterus, biliary obstruction, and splenomegaly with multiple diffuse splenic hypoechoic nodules. On day 21, a cholecystectomy was performed to remove the obstruction, followed by a liver biopsy and splenectomy. Cytology of the spleen and liver showed many small lymphocytes with intracytoplasmic granules (sGLs). Splenic and hepatic infiltration of neoplastic CD3/granzyme B-positive small cells and lymphocytic cholecystitis with granzyme B-negative small cells were noted. T-cell receptor gene clonal rearrangements were observed in the liver tissues. The dog was diagnosed with a hepatosplenic T-cell lymphoma (HSTCL) of sGLs concurrent with lymphocytic cholecystitis. The icterus resolved after surgery, but there was progressive elevation of liver enzyme levels. Toceranib was administered from day 39, resulting in decreased liver enzyme levels, and the dog remained in good condition. The dog stayed in remission after toceranib administration and survived for 460 days. Toceranib should be considered an effective treatment option for canine HSTCL. Full article

Objective: Canine cutaneous mast cell tumors (cMCTs) have variable rates of recurrence and metastasis. We evaluated how various prognostic factors affect survival, recurrence, and metastasis in dogs with cMCT who underwent surgery and vinblastine chemotherapy. Animals: 90 dogs with cMCT treated with surgery and vinblastine at a veterinary referral institution were included. Methods: Medical records were retrospectively reviewed. Prognostic factors were evaluated. Results: Most dogs (94%) had grade 2 or 3 cMCTs. Neoadjuvant vinblastine was used in 18 dogs, and none progressed locally before surgery. The use of neoadjuvant vinblastine was associated with a higher chance of local recurrence (p = 0.03) but not survival. Shorter survival times were found for tumors that were high-grade (p < 0.001), grade 3 (p < 0.001), or a MC of >5 (p < 0.001). Dogs with grade 2 tumors that were low-grade lived longer than those with high-grade tumors (p < 0.001). Histologic tumor-free margins and the ability to achieve local tumor control were not associated with outcome. Clinical Relevance: Both grading systems and MC were prognostic for survival in this population of dogs, supporting the need for the standard reporting of histopathologic findings. Neoadjuvant chemotherapy can be effective in downsizing cMCTs but does not influence survival. These findings are consistent with previous publications, showing the benefits of a more modern population of patients, surgical treatments, and histopathologic assessments. Full article

Cancer is the leading cause of death in companion animals. The evaluation of locoregional lymph nodes, known as lymph node mapping, is a critical process in assessing the stage of various solid tumors, such as mast cell tumors (MCTs), anal gland anal sac adenocarcinoma, melanoma, and mammary gland adenocarcinoma. MCTs are among the most prevalent skin malignancies in dogs. Staging is used to describe the extent of neoplastic disease, provide a framework for rational treatment planning, and evaluate treatment results. The aim of this review is to present the current knowledge on sentinel lymph node (SLN) mapping in canine MCTs, its influence on treatment decisions and prognosis, as well as the advantages and limitations of different SLN techniques currently available in veterinary oncology. A search methodology was adopted using the PubMed, Scopus, and Google Scholar databases. Critical analyses of up-to-date research have shown that lymphoscintigraphy can achieve a lymph node detection rate of between 91 and 100%. This method is becoming increasingly recognized as the gold standard in both human and veterinary medicine. In addition, initial studies on a limited number of animals have shown that computed tomographic lymphography (CTL) is highly effective in the SLN mapping of MCTs, with detection rates between 90 and 100%. The first study on contrast-enhanced ultrasound (CEUS) also revealed that this advanced technique has up to a 95% detection rate in canine MCTs. These methods provide non-ionizing alternatives with high detection capabilities. Furthermore, combining computed tomography and near-infrared fluorescence (NIR/NIR-LND) lymphography is promising as each technique identifies different SLNs. Indirect lymphography with Lipiodol or Iohexol is technically feasible and may be also used to effectively detect SLNs. The integration of these mapping techniques into routine MCT staging is essential for enhancing the precision of MCT staging and potentially improving therapeutic outcomes. However, further clinical trials involving a larger number of animals are necessary to refine these procedures and fully evaluate the clinical benefits of each technique. Full article

A cytological grading system for canine mast cell tumors (MCTs) has been developed, but its integration into clinical routine has been hindered due to its diagnostic limitations. The aim of this study was to assess the prognostic value of Ki-67 and argyrophilic nucleolar organizing region (AgNOR) markers in cytological MCT samples and to determine cut-off values for these markers in correlation with histopathological grading. Cytological samples were collected prior to surgical excision, and histopathological samples were obtained postsurgery from 45 dogs diagnosed with cutaneous mast cell tumors (MCTs). The cytological specimens were classified using a two-tier grading system, and their Ki-67 (average immunopositive nuclei per 100 cells) and AgNOR (average AgNOR counts per 100 nuclei) signaling was assessed. Through receiver operating characteristic (ROC) analysis, cut-off values for Ki-67 and Ki-67 × AgNOR were determined to better align with histopathological grading (classified as low or high grade according to Kiupel’s scoring system). Without the inclusion of proliferative markers, there was a 73% agreement between cytological and histopathological grading. The prediction of histopathological grade was slightly more accurate when assessing Ki-67 and Ki-67 × AgNOR signaling in cytological specimens (75% and 80%, respectively) compared to the initial cytological grading. The cytological assessment of canine MCTs proves beneficial for the initial evaluation, and the incorporation of the evaluation of Ki-67 and AgNOR markers may assist in identifying diagnostically highly malignant MCTs. Full article

Cell division through mitosis (microscopically visible as mitotic figures, MFs) is a highly regulated process. However, neoplastic cells may exhibit errors in chromosome segregation (microscopically visible as atypical mitotic figures, AMFs) resulting in aberrant chromosome structures. AMFs have been shown to be of prognostic relevance for some neoplasms in humans but not in animals. In this study, the prognostic relevance of AMFs was evaluated for canine cutaneous mast cell tumors (ccMCT). Histological examination was conducted by one pathologist in whole slide images of 96 cases of ccMCT with a known survival time. Tumor-related death occurred in 11/18 high-grade and 2/78 low-grade cases (2011 two-tier system). The area under the curve (AUC) was 0.859 for the AMF count and 0.880 for the AMF to MF ratio with regard to tumor-related mortality. In comparison, the AUC for the mitotic count was 0.885. Based on our data, a prognostically meaningful threshold of ≥3 per 2.37 mm² for the AMF count (sensitivity: 76.9%, specificity: 98.8%) and >7.5% for the AMF:MF ratio (sensitivity: 76.9%, specificity: 100%) is suggested. While the mitotic count of ≥ 6 resulted in six false positive cases, these could be eliminated when combined with the AMF to MF ratio. In conclusion, the results of this study suggests that AMF enumeration is a prognostically valuable test, particularly due to its high specificity with regard to tumor-related mortality. Additional validation and reproducibility studies are needed to further evaluate AMFs as a prognostic criterion for ccMCT and other tumor types. Full article