Breed predilections and prognosis for subungual squamous cell carcinoma in dogs.

Objective: To better document the prevalence, breed predilections, and clinical behavior of subungual squamous cell carcinomas in dogs. Procedure: Retrospective analysis of records from 278 812 canine biopsy submissions including 1518 subungual squamous cell carcinomas from dogs in Canada between the years 2003 and 2021. Results: In agreement with previous studies, giant schnauzers [odds ratio (OR): 56.7], standard schnauzers (OR: 20.3), Gordon setters (OR: 18.3), black standard poodles (OR: 11.1), Kerry blue terriers (OR: 9.4), Rottweilers (OR: 7.0), and several other breeds of large black dogs had a strong predilection for development of subungual squamous cell carcinomas. In giant schnauzers and standard poodles specifically, the risk of developing additional tumors on additional digits was 56%. There were no local postoperative recurrences, and the risk of detecting metastatic disease within 5 y after initial diagnosis was very low at 4%. Conclusion: Moderately large black, or black and tan, dogs have a marked increase in the prevalence of subungual squamous cell carcinomas. At least in giant schnauzers and black standard poodles, the risk of developing additional similar tumors on additional digits is high, but the metastatic risk is very low. Clinical relevance: Veterinarians receiving a histologic diagnosis of subungual squamous cell carcinoma in a large black (or predominantly black) dog should advise the owners of a substantial risk that the dog will develop similar tumors on other digits in 2 or 3 y following initial diagnosis, but that the risk of local recurrence or metastatic spread is extremely low.

Objectif: Mieux documenter la prévalence, les préférences de race et le comportement clinique des carcinomes épidermoïdes sous-unguéaux chez les chiens. Procédure: Analyse rétrospective des dossiers de 278 812 soumissions de biopsies canines, y compris 1518 carcinomes épidermoïdes sous-unguéaux de chiens au Canada entre 2003 et 2021. Résultats: En accord avec les études précédentes, les schnauzers géants [rapport de cotes (OR): 56,7], les schnauzers standards (OR: 20,3), les setters Gordon (OR: 18,3), les caniches standards noirs (OR: 11,1), les Kerry blue terriers (OR: 9,4), Rottweilers (OR: 7,0) et plusieurs autres races de grands chiens noirs avaient une forte prédilection pour le développement de carcinomes épidermoïdes sous-unguéaux. Chez les schnauzers géants et les caniches standards en particulier, le risque de développer des tumeurs supplémentaires sur des doigts additionnels était de 56 %. Il n'y a pas eu de récidive postopératoire locale et le risque de détecter une maladie métastatique dans les 5 ans suivant le diagnostic initial était très faible à 4 %. Conclusion: Les chiens noirs ou noirs et brun-roux de taille moyenne présentent une augmentation marquée de la prévalence des carcinomes épidermoïdes sous-unguéaux. Au moins chez les schnauzers géants et les caniches standards noirs, le risque de développer des tumeurs similaires supplémentaires sur des doigts additionnels est élevé, mais le risque métastatique est très faible. Pertinence clinique: Les vétérinaires qui reçoivent un diagnostic histologique de carcinome épidermoïde sous-unguéal chez un gros chien noir (ou à prédominance noire) doivent informer les propriétaires d'un risque substantiel que le chien développe des tumeurs similaires sur d'autres doigts dans les 2 ou 3 ans suivant le diagnostic initial, mais que le risque de récidive locale ou de propagation métastatique est extrêmement faible.(Traduit par Dr Serge Messier).

A retrospective study of 44 canine apocrine sweat gland adenocarcinomas.

Apocrine sweat gland adenocarcinomas (AACs) are relatively uncommon skin tumors in dogs. Little prognostic or behavioral information has been published for these tumors. In this retrospective study, 44 AACs from diagnostic archives were reexamined and clinical postexcisional follow-ups for 25 of the 44 cases were obtained by a survey. There were 28 out of 44 (65.9%) AACs that invaded the capsule, stroma, or both, 5 of 44 (11.4%) invaded blood vessels and stroma, and 1 out of 25 (4%) had distant metastases. The presence or absence of stromal and vascular invasion was predicted by clinical examination with more than 80% accuracy. Postexcisional median survival of dogs with AACs was 30 mo at the time of survey. Determination of a correlation between histological features and malignant behavior of AACs was compromised by the low number of cases with clinical AAC-related problems; however, it appears that intravascular invasion is an important indicator of potential systemic metastases.

Canine choroidal melanoma with metastases.

A 3-year-old-female, spayed Golden Retriever was examined for a unilateral retinal detachment with exophthalmos. Ultrasonographically, a mass was detected with intra- and extraocular extension. The orbit was exenterated and the dog recovered uneventfully. Histopathologic diagnosis was a primary choroidal melanoma with orbital extension, however, the behavioral and cytologic features were benign. Routine examinations postsurgically were nonremarkable. Twenty-one months after surgery the dog was euthanized for respiratory collapse with radiographic signs of metastasis. Necropsy revealed black lesions in the lung and liver. Histopathologic diagnosis was metastatic melanoma with morphology and behavior identical to the primary choroidal melanoma. This is the first definitive case of a canine choroidal melanoma with metastasis.