Comparison of harmonic shears, diode laser, and scissor cutting and suturing for caudal palatoplasty in dogs with brachycephalic obstructive airway syndrome.

Traditionally, staphylectomy has been performed using scissors cutting and suturing. Alternative surgical techniques such as staphylectomy with monopolar electrocoagulation, CO2 or diode laser, bipolar vessel sealing device and harmonic shears have also been described. The purpose of this prospective study was to compare the difference in surgical time, intraoperative haemorrhage and histological damage between staphylectomy performed with harmonic shears (HSS), diode laser (DLS) and traditional scissor 'cutting and suturing' technique with Metzenbaum scissors (SIS). Group HSS included 17 dogs, whereas Group DLS and Group SIS included 10 dogs each. Double masked histological evaluation was performed on the excised specimens. The harmonic shears resulted in the shortest surgical times (HSS 46 s, DLS 300 s, SIS 360 s; P < 0.001). There was a difference in the intraoperative haemorrhage among the three techniques; intraoperative haemorrhage did not occur in HSS and DLS groups. HSS was associated with more frequent damage involving the connective tissue (P = 0.001), muscle (P = 0.038), salivary gland tissue (P < 0.001), but less oedema was observed (P < 0.001). HSS was the fastest of the techniques evaluated for caudal elongated soft palate resection, resulting in less tissue oedema, and no intra-operative haemorrhage. These characteristics might result in reduced postoperative swelling and airway obstruction compared to other techniques.

Use of cytology for canine mammary masses and perceived diagnostic utility in four European countries.

OBJECTIVES: To investigate the use of cytology of canine mammary masses and its perceived diagnostic utility in four European countries. MATERIALS AND METHODS: The link to a web-based questionnaire was sent to veterinarians of Italy, UK, Greece and Spain. The questionnaire contained basic questions regarding the respondents' background, their general use of cytology as a diagnostic tool, the incidence of canine mammary tumours within their clinics and their use of cytology for canine mammary masses. Multiple binary and ordinal logistics models were used to evaluate associations between variables. RESULTS: Four hundred and sixty-five veterinarians completed the survey (Italy: 114; UK: 66; Greece: 55; Spain: 230). Most veterinarians working in each country used cytology as a diagnostic tool, although only 43.0%, 54.6%, 43.6% and 36.5% used cytology for the investigation of CMMs in Italy, UK, Greece and Spain respectively. Supposing the cytology were able to correctly differentiate benign versus malignant canine mammary masses, the percentage of veterinarians using this test would increase in Italy, UK and Greece (Italy: 91.2%; UK: 93.9%; Greece: 96.4%); however, this was not reflected by veterinarians working in Spain (51.7%). CLINICAL SIGNIFICANCE: If cytology of canine mammary masses were able to differentiate between benign and malignant, most veterinarians in Italy, UK and Greece would utilise the technique, justifying further research into the diagnostic accuracy of this test. Spanish veterinarians were significantly different and further research into why these individuals would not value the ability of cytology to differentiate between benign and malignant may be of value.

Comparison of minichromosome maintenance protein 7, Ki67 and mitotic index in the prognosis of intermediate Patnaik grade cutaneous mast cell tumours in dogs.

A previous study found that minichromosome maintenance protein 7 (MCM7) score was associated with prognosis in dogs with cutaneous mast cell tumours (MCTs) independent of histological grade. The primary aim of this study was to validate this score in a different cohort of dogs focusing exclusively on patients with Patnaik intermediate grade MCTs treated with surgery alone and followed for a minimum of 1 year. A secondary aim was to evaluate the prognostic performance of MCM7 in relation to Kiupel histological grade, mitotic index (MI) and Ki67 index in the same cohort of dogs. Ninety dogs were identified, 82 were low Kiupel grade and 8 were high Kiupel grade. Seventy-two dogs were alive after a median follow-up of 1136 days and 18 dogs died of MCT-related causes after a median of 116 days. A MI threshold of 5 was associated with a sensitivity of 0.39 and a specificity of 0.99 in predicting MCT-related death; for Ki67 a threshold of 0.018 was associated with a sensitivity of 0.78 and a specificity of 0.83; and for MCM7 a threshold of 0.18 gave a sensitivity of 0.83 and a specificity of 0.86. Combining MI, Ki67 and MCM7 showed an improved accuracy of predicting death compared with each individual variable. Therefore, performing Ki67 and MCM7 in dogs with GII MCT, low Kiupel grade and low MI might be a consideration.

Prognostic significance of histopathology in canine anal sac gland adenocarcinomas: Preliminary results in a retrospective study of 39 cases.

Metastatic rates and survival times of canine anal sac gland adenocarcinomas (ASGACs) vary among studies, making prognostication difficult. Little is known about the prognostic significance of histopathology of ASGACs. This retrospective study investigated associations between histological features, clinical presentation and outcome for 39 ASGACs. Most tumours were incompletely excised (62%) and had moderate to marked peripheral infiltration (74%). The predominant growth pattern was solid, tubules/rosettes/pseudorosettes and papillary in 49%, 46% and 5% of the cases, respectively. Nuclear pleomorphism was either moderate (77%) or mild (23%). Necrosis and lymphovascular invasion were present in 54% and 10% of the cases, respectively. All histological features except mitotic count and necrosis were associated with nodal metastasis at presentation. A statistically significant poorer outcome was identified for tumours with a solid growth pattern, moderate or marked peripheral infiltration, necrosis and lymphovascular invasion. These results need further validation in a larger cohort of dogs.

Assessment of Lymphoid Molecular Clonality in Canine Thymoma.

The aim of this study was to document the molecular clonality of lymphoid cells in canine thymoma using polymerase chain reaction for antigen receptor rearrangement (PARR). Fifteen formalin-fixed and paraffin wax-embedded samples of canine thymoma were analyzed for T- and B-cell receptor clonality. Two of these 15 cases were excluded from the study due to insufficient DNA concentration. Twelve of the 13 remaining samples (92.3%) showed a polyclonal lymphoid component and in one case the lymphoid component was monoclonal (T-cell clonality). PARR could therefore be a useful tool for differentiating canine thymoma from canine mediastinal lymphoma.

Primary ureteral leiomyosarcoma in a dog.

CASE DESCRIPTION: A nearly 6-year-old female spayed Labrador Retriever was presented for acute abdominal pain and lethargy. The dog had no previous health concerns apart from occasional episodes of urinary incontinence in the 2 months prior to presentation. A retroperitoneal mass involving the right ureter was found during the investigations. Serum urea was mildly elevated, but the serum creatinine was within the normal range. No distant metastases were detected. A right ureteronephrectomy was performed. The ureteral mass was confirmed as a leiomyosarcoma and completely excised. The kidney was histologically normal. Unfortunately, during a routine 3-month postoperative assessment, a recurrent mass at the previous retroperitoneal surgical site was confirmed by biopsy to be a leiomyosarcoma. Courses of doxorubicin and chlorambucil were given, but failed to halt the progression of the recurrent mass. The dog was euthanised 5.5 months postoperatively because of poor quality of life. CLINICAL RELEVANCE: Ureteral leiomyosarcoma should be on the differential diagnosis list for a retroperitoneal mass, possibly causing severe abdominal pain with minor clinical signs associated with the urinary tract. This dog in this reported case of ureteral leiomyosarcoma had a short survival time, despite complete surgical excision and chemotherapy, because of local recurrence.

Intra- and inter-observer agreement in histological assessment of canine soft tissue sarcoma.

BACKGROUND: The diagnosis of canine soft tissue sarcoma (STS) is based on histological assessment. Assessment of criteria such as, degree of differentiation, necrosis score and mitotic score, gives rise to a final tumour grade, which is important in the recommendation of treatment and prognosis of patients. MATERIALS AND METHODS: Previously diagnosed cases of STS were independently assessed by three board-certified veterinary pathologists. Participating pathologists were blinded to the original results. For the intra-observer study, the cases were assessed by a single pathologist six months apart and slides were randomized between readings. For the inter-observer study, the whole case series was assessed by a single pathologist before being passed onto the next pathologist. Intraclass correlation coefficient (ICC) and Fleiss's Kappa (ƙ) for the intra- (single observer) and inter-observer agreement. RESULTS: Strong agreement was observed for the intra-observer assessment in necrosis score, mitotic score, total score and tumour grading (ICC between 0.78 to 0.91). The intra-observer agreement for differentiation score was rated perfect (ICC 1.00). The agreement between pathologists for the diagnosis and grading of canine STS was moderate (ƙ = 0.60 and 0.43 respectively). CONCLUSION: Histological assessment of canine STS had high reproducibility by an individual pathologist. The agreement of diagnosis and grading of canine STS was moderate between pathologists. Future studies are required to investigate further assessment criteria to improve the specificity of STS diagnosis and the accuracy of the STS grading in dogs.

Comparison of the use of LigaSure versus a standard technique for tonsillectomy in dogs.

The principal aim of this study was to document the effectiveness of tonsillectomy in dogs using a vessel-sealing device compared with a standard technique with tonsillectomy forceps. A secondary aim of the study was to document histopathological changes of the excised tonsillar tissue in dogs with brachycephalic obstructive airway syndrome. 20 dogs were studied. The time taken to remove a tonsil using LigaSure was a mean of 44.8 seconds (sd 15 seconds, 95 per cent CI 40  to 57 seconds) and with the standard technique a mean of 305.9 seconds (sd 67 seconds, 95 per cent CI 272  to 349 seconds). Significantly less haemorrhage occurred using LigaSure compared with the standard technique. Histopathology of the tonsils was characterised by multifocal neutrophilic and lymphocytic inflammation, and 1-2 mm of heat-induced coagulation necrosis at the cut edge of LigaSure tonsils. This study shows that LigaSure is significantly faster and resulted in less bleeding than the standard technique.

Evaluation of Minichromosome Maintenance Protein 7 and c-KIT as Prognostic Markers in Feline Cutaneous Mast Cell Tumours.

Mast cell tumours (MCTs) are a common skin tumour in cats, but there is currently no histological grading system or reliable prognostic marker for this species (unlike the situation for dogs). This study utilized a set of 71 feline cutaneous MCTs with known clinical outcomes to assess the potential of various prognostic markers, including the cellular proliferation marker minichromosome maintenance protein (MCM)-7, mitotic index and various KIT labelling characteristics, including KIT positivity, KIT labelling pattern and KIT immunoreactivity score (IS). Of the factors studied, the mitotic index and the KIT labelling pattern were the only features associated significantly with survival times, while the proliferation marker MCM7 and the KIT IS were not. The study also highlights the variability of KIT labelling characteristics between tumours, which may prevent use of this marker as a diagnostic and prognostic tool.

Prognostic evaluation of feline mammary carcinomas: a review of the literature.

A large number of studies have investigated feline mammary tumors in an attempt to identify prognostic markers and generate comparative analyses with human breast cancer. Nevertheless, a retrospective base of assessments and the lack of standardization in methodology and study design have caused weakness in study results, making comparison difficult. We examined feline mammary tumor publications and evaluated postulated prognostic parameters according to the recently published "Recommended Guidelines for the Conduct and Evaluation of Prognostic Studies in Veterinary Oncology." Using these criteria, we determined with statistically significant reliability that prognostic parameters for feline mammary tumors are tumor grading and lymph node/lymphovascular invasion. Furthermore, tumor subtype, size, and staging are worthy of further standardized investigation. We present statistical significance for each studied parameter as well as its relevance to disease progression and survival. Our evaluation suggests that marker expression (ie, Ki67, HER2, ER) may provide relevant information applicable for therapeutic predictions; however, consensus efforts and protocol standardization are needed. We identify and discuss major points of concern--such as sample preservation and selection, standardization of immunohistochemical protocols, and evaluation of results--to provide support for subsequent reliable analyses.

Oestrogen and progesterone receptor expression in subtypes of canine mammary tumours in intact and ovariectomised dogs.

The objective of this study was to investigate as a potential prognostic indicator the relationship between histological subtype of canine mammary tumours (CMTs) and oestrogen-α (ORα) and progesterone (PR) receptor expression. Using immunohistochemistry, receptor expression in neoplastic epithelial cells was assessed in 12 different subtypes in 113 CMTs (34 benign, 79 malignant) and 101 surrounding normal tissues. Sixty-eight and 45 CMTs were from intact and ovariectomised bitches, respectively. Histological subtype strongly influenced ORα/PR expression: simple and complex adenomas as well as simple tubular carcinomas exhibited the greatest expression, whereas immunohistochemical labelling for these receptors was weakest in carcinoma and malignant myoepitheliomas, as well as in solid/anaplastic carcinomas and comedocarcinomas. Receptor expression was generally higher in benign relative to malignant neoplasms, and in the latter it was significantly lower in ovariectomised vs. intact bitches. Lymphatic invasion, mitotic index, nodule diameter, and tumour grade were significantly associated with ORα/PR expression. Although not found to be an independent prognostic indicator, tumours from dogs with <10% cells with ORα/PR expression had a poorer prognosis. Lymphatic invasion, the state of the margins of excision, and mitotic index were found to be independent prognostic indicators. Overall, the results suggest that differences in histological subtype and whether or not a bitch has been ovariectomised should be considered when evaluating the significance of ORα and PR expression in CMTs.

The dog as a natural animal model for study of the mammary myoepithelial basal cell lineage and its role in mammary carcinogenesis.

Basal-like tumours constitute 2-18% of all human breast cancers (HBCs). These tumours have a basal myoepithelial phenotype and it has been hypothesized that they originate from either myoepithelial cells or mammary progenitor cells. They are heterogeneous in morphology, clinical presentation, outcome and response to therapy. Canine mammary carcinomas (CMCs) have epidemiological and biological similarities to HBCs, are frequently biphasic and are composed of two distinct neoplastic populations (epithelial and myoepithelial). The present study evaluates the potential of CMCs as a natural model for basal-like HBCs. Single and double immunohistochemistry was performed on serial sections of 10 normal canine mammary glands and 65 CMCs to evaluate expression of cytokeratin (CK) 8/18, CK5, CK14, α-smooth muscle actin (SMA), calponin (CALP), p63 and vimentin (VIM). The tumours were also evaluated for Ki67 and human epidermal growth factor receptor (HER)-2 expression. A hierarchical model of cell differentiation was established, similar to that for the human breast. We hypothesized that progenitor cells (CK5(+), CK14(+), p63(+) and VIM(+)) differentiate into terminally-differentiated luminal glandular (CK8/18(+)) and myoepithelial (CALP(+), SMA(+) and VIM(+)) cells via intermediary luminal glandular cells (CK5(+), CK14(+) and CK8/CK18(+)) and intermediary myoepithelial cells (CK5(+), CK14(+), p63(+), SMA(+), CALP(+) and VIM(+)). Neoplastic myoepithelial cells in canine complex carcinomas had labelling similar to that of terminally-differentiated myoepithelial cells, while those of carcinomas-and-malignant myoepitheliomas with a more aggressive biological behaviour (i.e. higher frequency of vascular/lymph node invasion and visceral metastases and higher risk of tumour-related death) were comparable with intermediary myoepithelial cells and had significantly higher Ki67 expression. The majority of CMCs examined were negative for expression of HER-2. The biphasic appearance of CMCs with involvement of the myoepithelial component in different stages of cell differentiation may help to define the role of myoepithelial cells in the mammary carcinogenetic process and the heterogeneous nature of basal-like HBCs.

Proposed classification of the feline "complex" mammary tumors as ductal and intraductal papillary mammary tumors.

When compared with the canine species, feline mammary tumors (FMTs) are much less heterogeneous, with a predominance of simple malignant neoplasm. Benign FMTs are rare, and it is unclear if complex and mixed tumors exist in the feline. In this study, we selected for immunohistochemical analyses 12 FMTs that had unusual histologic features. A group of 8 (2 benign and 6 malignant) FMTs showed a biphasic epithelial/myoepithelial population and a very regular cord-like distribution in a "Chinese lettering" pattern, within ectatic ducts. A second group (2 benign and 2 malignant) had an intraductal epithelial papillary growth pattern with a basally located monolayer of myoepithelial cells and a supporting fibrovascular stroma. The myoepithelial component always produced a standard immunohistochemical signature. All malignancies were grade I, and the subjects were all alive at 1 year postdiagnosis. On the basis of their morphology, we propose that they be classified as feline ductal adenoma/carcinoma and feline intraductal papillary adenoma/carcinoma, respectively. They overlap with their canine counterparts and lack the typical myoepithelial differentiation patterns seen in canine complex neoplasms, and therefore, the term complex should be avoided in felines. This study will add new information on FMT classification and be useful for prognostic studies.

A retrospective study of those histopathologic parameters predictive of invasion of the lymphatic system by canine mammary carcinomas.

The aim of the present study was to determine which histopathologic parameters of primary canine mammary carcinomas (CMCs) could predict metastatic spread via the lymphatic system. A modification of the World Health Organization classification was applied to 245 CMCs. In addition to tumor subtype, neoplastic infiltration of the surrounding mammary stroma, vasculogenic mimicry, and micropapillary pattern were evaluated, and 2 histologic grading systems were used for each sample. A statistical analysis was undertaken to determine the relationship between these histopathologic parameters and the detection of lymphatic vessels invasion (LVI) and regional lymph node metastases (RLM). To compare the predictive value for lymphatic spread of the 2 histologic grading systems, the Akaike information criterion was measured. The classification into tumor subtypes was significant (P < .01) in predicting the risk of LVI and RLM. Peripheral infiltration, vasculogenic mimicry, and micropapillary pattern were found in 170 of 245 (69.4%), 32 of 245 (13.1%), and 54 of 245 (22.0%) CMCs. The presence of peripheral infiltration was significantly associated (P < .001) with both LVI and RLM, and a similar relation (P < .05) was found for the micropapillary pattern. Vasculogenic mimicry was not predictive of invasion of the lymphatic system. Both histologic grading systems were significant predictors (P < .001) of the risk of LVI and RLM. The grading system that included a more rigorous evaluation of the neoplastic mitotic activity had the lower Akaike information criterion values, thus indicating a better predictive ability. The study confirms the significant prognostic role for the modified World Health Organization classification of CMCs and the prognostic value of additional histopathologic parameters.

Classification and grading of canine mammary tumors.

Mammary neoplasms are the most common neoplasm in female dogs. Two histologic classification systems for canine mammary tumors and dysplasias have been published: the first in 1974 and a modification in 1999. This article provides a brief overview of the two histologic classification systems. Since the publication of the second system, several new histologic subtypes of canine mammary neoplasms have been described. These have been incorporated into the proposed new classification system. This article also compares the grading systems for canine mammary carcinomas and their use for prognosis, along with the histologic classification.

Development, anatomy, histology, lymphatic drainage, clinical features, and cell differentiation markers of canine mammary gland neoplasms.

Mammary neoplasms are the most common neoplasm in female dogs. This article describes the embryologic development, normal anatomy, and histology of the canine mammary gland from the onset of first estrous and the changes that occur in the mammary gland during the estrus cycle. The clinical features of canine mammary gland tumors and their relation to prognosis are discussed, including age, hormones, breed, diet, and obesity. Additional clinical prognostic factors including clinical presentation, tumor size, and lymph node status at the time of presentation are discussed in relation to diagnosis and tumor staging. Immunohistochemical evaluation of the cell differentiation markers of the normal and neoplastic canine mammary gland is described and compared with similar studies in humans; the ways these markers may be used to assist with the prognosis of canine mammary neoplasms are discussed.

An Immunohistochemical study of HER-2 expression in feline mammary tumours.

The aim of the present study was to evaluate HER-2 expression in feline mammary tumours. Five different immunohistochemical protocols were tested with 73 feline mammary carcinomas (MCs), 10 mammary adenomas and 73 hyperplastic or dysplastic mammary lesions. The histological features of these lesions, clinical follow-up and expression of Ki-67 and p53 were also examined. With an optimized immunohistochemical protocol, HER-2 overexpression was detected in only four of the 73 (5.5%) MCs and did not correlate with histological classification or with the 1 year post-surgical clinical outcome. No correlation was found between the expression of Ki-67 or p53 and HER-2. Five of the 73 (6.8%) hyperplastic or dysplastic lesions and one of the 10 (10%) mammary adenomas were HER-2 positive. These results suggest that HER-2 may not play as significant role in mammary carcinogenesis and prognosis in cats as it does in human patients.