Prognostic Significance of Canine Mammary Tumor Histologic Subtypes: An Observational Cohort Study of 229 Cases

Histopathology is considered the gold standard diagnostic method for canine mammary tumors. In 2011, a new histologic classification for canine mammary tumors was proposed. The present study was a 2-year prospective study that validated the 2011 classification as an independent prognostic indicator with multivariate analysis in a population of 229 female dogs, identifying subtype-specific median survival times (MST) and local recurrence/distant metastasis rates. Dogs with benign tumors and carcinoma arising in benign mixed tumors all had an excellent prognosis. Dogs with complex carcinoma and simple tubular carcinoma also experienced prolonged survival. Those with simple tubulopapillary carcinoma, intraductal papillary carcinoma, and carcinoma and malignant myoepithelioma had a more than 10-fold higher risk of tumor-related death. The prognosis was even worse for adenosquamous carcinoma (MST = 18 months), comedocarcinoma (MST = 14 months), and solid carcinoma (MST = 8 months). The most unfavorable outcome was for anaplastic carcinoma (MST = 3 months) and carcinosarcoma (MST = 3 months), which also had the highest metastatic rates (89% and 100%, respectively). Adenosquamous carcinoma exhibited the highest local recurrence rate (50%). In the same canine population, the tumor diameter was recognized as a strong predictor of local recurrence/distant metastasis and an independent prognosticator of survival in the multivariate analysis. Excision margins were predictive only of local recurrence, whereas lymphatic invasion and histologic grade were predictive of local recurrence/distant metastasis and survival, although only in univariate analyses. In conclusion, this study validated the 2011 classification scheme and provided information to be used in the clinical setting and as the basis for future prognostic studies. </jats:p

A Retrospective Study of Clinical and Histopathological Features of 81 Cases of Canine Apocrine Gland Adenocarcinoma of the Anal Sac: Independent Clinical and Histopathological Risk Factors Associated with Outcome.

Canine apocrine gland anal sac adenocarcinoma (AGASAC) is a malignant tumour with variable clinical progression. The objective of this study was to use robust multivariate models, based on models employed in human medical oncology, to establish clinical and histopathological risk factors of poor survival. Clinical data and imaging of 81 cases with AGASAC were reviewed. Tissue was available for histological review and immunohistochemistry in 49 cases. Tumour and lymph node size were determined using the response evaluation criteria in the solid tumours system (RECIST). Modelling revealed tumour size over 2 cm, lymph node size grouped in three tiers by the two thresholds 1.6 cm and 5 cm, surgical management, and radiotherapy were independent clinical variables associated with survival, irrespective of tumour stage. Tumour size over 1.3 cm and presence of distant metastasis were independent clinical variables associated with the first progression-free interval. The presence of the histopathological variables of tumour necrosis, a solid histological pattern, and vascular invasion in the primary tumour were independent risk factors of poor survival. Based upon these independent risk factors, scoring algorithms to predict survival in AGASAC patients are presented

Reproducibility and Feasibility of Classification and National Guidelines for Histological Diagnosis of Canine Mammary Gland Tumours: A Multi-Institutional Ring Study

Histological diagnosis of Canine Mammary Tumours (CMTs) provides the basis for proper treatment and follow-up. Nowadays, its accuracy is poorly understood and variable interpretation of histological criteria leads to a lack of standardisation and impossibility to compare studies. This study aimed to quantify the reproducibility of histological diagnosis and grading in CMTs. A blinded ring test on 36 CMTs was performed by 15 veterinary pathologists with different levels of education, after discussion of critical points on the Davis-Thompson Foundation Classification and providing consensus guidelines. Kappa statistics were used to compare the interobserver variability. The overall concordance rate of diagnostic interpretations of WP on identification of hyperplasia-dysplasia/benign/malignant lesions showed a substantial agreement (average k ranging from 0.66 to 0.82, with a k-combined of 0.76). Instead, outcomes on ICD-O-3.2 morphological code /diagnosis of histotype had only a moderate agreement (average k ranging from 0.44 and 0.64, with a k-combined of 0.54). The results demonstrated that standardised classification and consensus guidelines can produce moderate to substantial agreement; however, further efforts are needed to increase this agreement in distinguishing benign versus malignant lesions and in histological grading. View Full-Tex

Standardization of canine meningioma grading: Validation of new guidelines for reproducible histopathologic criteria

Canine meningiomas are currently graded using the human grading system. Recently published guidelines have adapted the human grading system for use in dogs. The goal of this study was to validate the new guidelines for canine meningiomas. To evaluate the inter‐observer agreement, 5 veterinary surgical pathologists graded 158 canine meningiomas following the human grading system alone or with the new guidelines. The inter‐observer agreement for histologic grade and each of the grading criteria (mitotic grade, invasion, spontaneous necrosis, macronucleoli, small cells, hypercellularity, pattern loss and anaplasia) was evaluated using the Fleiss kappa index. The diagnostic accuracy (sensitivity and specificity) was assessed by comparing the diagnoses obtained with the 2 grading systems with a consensus grade (considered the reference classification). The consensus histologic grade was obtained by agreement between 4 experienced veterinary neuropathologists following the guidelines. Compared with the human grading alone, the canine‐specific guidelines increased the inter‐observer agreement for: histologic grade (κ = 0.52); invasion (κ = 0.67); necrosis (κ = 0.62); small cells (κ = 0.36); pattern loss (κ = 0.49) and anaplasia (κ = 0.55). Mitotic grade agreement remained substantial (κ = 0.63). The guidelines improved the sensitivity in identifying grade 1 (95.6%) and the specificity in identifying grade 2 (96.2%) meningiomas. In conclusion, the new grading guidelines for canine meningiomas are associated with an overall improvement in the inter‐observer agreement and higher diagnostic accuracy in diagnosing grade 1 and grade 2 meningiomas

Standardization of canine meningioma grading: Validation of new guidelines for reproducible histopathologic criteria.

Canine meningiomas are currently graded using the human grading system. Recently published guidelines have adapted the human grading system for use in dogs. The goal of this study was to validate the new guidelines for canine meningiomas. To evaluate the inter-observer agreement, 5 veterinary surgical pathologists graded 158 canine meningiomas following the human grading system alone or with the new guidelines. The inter-observer agreement for histologic grade and each of the grading criteria (mitotic grade, invasion, spontaneous necrosis, macronucleoli, small cells, hypercellularity, pattern loss and anaplasia) was evaluated using the Fleiss kappa index. The diagnostic accuracy (sensitivity and specificity) was assessed by comparing the diagnoses obtained with the 2 grading systems with a consensus grade (considered the reference classification). The consensus histologic grade was obtained by agreement between 4 experienced veterinary neuropathologists following the guidelines. Compared with the human grading alone, the canine-specific guidelines increased the inter-observer agreement for: histologic grade (κ = 0.52); invasion (κ = 0.67); necrosis (κ = 0.62); small cells (κ = 0.36); pattern loss (κ = 0.49) and anaplasia (κ = 0.55). Mitotic grade agreement remained substantial (κ = 0.63). The guidelines improved the sensitivity in identifying grade 1 (95.6%) and the specificity in identifying grade 2 (96.2%) meningiomas. In conclusion, the new grading guidelines for canine meningiomas are associated with an overall improvement in the inter-observer agreement and higher diagnostic accuracy in diagnosing grade 1 and grade 2 meningiomas

Aspetti classificativi, epidemiologici, prognostici e profili di espressione proteica del tumore mammario del cane

Mammary tumors are the most common neoplasms in female dogs. Available data regarding the etiopathogenesis, the epidemiology and the biological behavior of this type of tumor are still incomplete and controversial. It is widely known that they are highly heterogeneous in morphology and that the lack of precise histopathological diagnostic criteria does not allow an adequate standardization of the diagnosis. Based on these considerations, and as a part of an international collaboration, we studied in details some aspects regarding the classification of these neoplasms. This allowed us to define precise criteria for the distinction between benign and malignant mammary tumors and to write a new classification for the hyperplastic/dysplastic and neoplastic lesions of canine mammary gland. The new classification is a modification of the internationally accepted WHO classification and incorporates some new morphological entities. These standardized criteria were applied on 2143 samples of canine mammary tissue. Other specific morphological characteristics were also evaluated. Relations between all the results obtained, and signalment, and follow-up data were investigated to improve the knowledge about the epidemiology and biological behavior of canine mammary tumors. We noticed that some dog breeds were less represented as carriers of malignant tumors and that in general the incidence of malignant tumor increased with age. In addition, we found that spayed animals, compared to intact ones, tend to have slightly different, apparently more aggressive, mammary tumors. For many tumors subtypes a specific biological behavior was recognized. Of particular interest was the immunohistochemical study of a new tumor subtype (carcinoma and malignant myoepithelioma) characterized by the presence of malignant myoepithelial cells. The prognostic value of different parameters such as tumor diameter, invasion of the lymphatic system, grade of malignancy, presence of peripheral infiltration and of a micropapillary pattern were discussed in details.Il tumore mammario è la neoplasia più frequente nei cani femmina. I dati relativi all’eziopatogenesi, all’epidemiologia e al comportamento biologico di questa forma tumorale sono ancora in parte incompleti e controversi. È risaputo inoltre che tale forma tumorale è caratterizzata da un’elevata eterogeneità morfologica e la mancanza di precisi e definiti criteri diagnostici istopatologici rende spesso difficile un’adeguata standardizzazione nella formulazione della diagnosi. Da queste considerazioni è nata l’esigenza di approfondire alcuni aspetti classificativi nell’ambito di una collaborazione internazionale che ha portato alla definizione di criteri precisi per la distinzione tra forme neoplastiche benigne e maligne e alla stesura di una nuova classificazione per le lesioni iperplastiche/neoplastiche della mammella del cane. Tale classificazione si ispira al precedente sistema classificativo internazionale (WHO), ma risulta rielaborata e integrata con alcune nuove entità morfologiche. Applicando questi criteri e la nuova classificazione su 2143 campioni di tessuto mammario canino e mettendo i risultati ottenuti in relazione ad altre specifiche valutazioni morfologiche e a dati segnaletici e di follow-up è stato possibile mettere in risalto alcuni aspetti, in parte noti e in parte nuovi, relativi all’epidemiologia e al comportamento biologico di questa forma tumorale. Si sono ad esempio messi in evidenza la presenza di razze meno rappresentate tra i soggetti portatori di tumori mammari maligni, un aumento di incidenza delle forme maligne al crescere dell’età e una certa tendenza degli animali sterilizzati, rispetto agli interi, a presentare forme tumorali leggermente diverse, apparentemente più aggressive. Per molte delle tipologie tumorali descritte è stato riconosciuto un comportamento biologico specifico. È stato particolarmente interessante a fini classificativi e prognostici approfondire lo studio, con ausilio immunoistochimico, di una nuova tipologia tumorale (carcinoma e mioepitelioma maligno) caratterizzata dalla presenza di cellule mioepiteliali maligne. È stata inoltre dimostrata o in altri casi confermata e dettagliata, la valenza prognostica di alcuni parametri quali il diametro tumorale, l’invasione del sistema linfatico, il grado istologico di malignità, l’infiltrazione periferica e la presenza di pattern micropapillare

Small intestinal peripheral nerve sheath tumour in a cat

Case summary A 5-year-old female spayed Chinchilla cat presented with a 4 week history of weight loss and inappetence. A thorough clinical investigation confirmed the presence of a distal jejunal mass. Histopathological and immunohistochemical analysis was consistent with a small intestinal peripheral nerve sheath tumour. Relevance and novel information To the best of our knowledge, this is the first reported case of a small intestinal peripheral nerve sheath tumour in a cat. This case report demonstrates the use of immunohistochemistry in differentiating this entity from other mesenchymal neoplasms. The veterinary literature available in this field is very limited and this report adds a new differential diagnosis to feline patients presenting with an intestinal mass

Glucose transporter-1 (Glut-1) expression in canine soft tissue sarcomas

No abstract available