A Cross-Sectional Study on Canine and Feline Anal Sac Disease

Limited data are available on canine and feline non-neoplastic anal sac disease. Therefore, the aim of this study was to obtain observational data on the incidence, predisposing factors, diagnosis, treatment, and recurrence rate of canine and feline anal sac disease. To this end, a questionnaire was distributed among veterinarians. The incidence of non-neoplastic anal sac disease was estimated at 15.7% in dogs and 0.4% in cats. Predisposing factors were diarrhea, skin problems, several dog breeds, and particularly small breed dogs, male cats, British shorthairs, and obesity in dogs. Diagnosis was made based on the presence of clinical signs and characteristics of the anal sac content. Manual expression and treating any potential underlying disease were the most important treatments for all three types of non-neoplastic anal sac disease. Anal sacculectomy was performed in refractory cases. The most recurrent anal sac disease condition was impaction. Diagnosis of anal sac disease should be based on clinical signs and rectal examination, as the evaluation of the anal sac content is not reliable. Surgical outcomes of anal sacculectomy can be improved when surgery is performed after medical management. Future studies should investigate these findings in prospective trials.

Whole-body thermal therapy as adjuvant therapy to radiation in a dog with metastasized anal sac adenocarcinoma

An eleven-year-old Galgo Espagnol was diagnosed with metastasized anal sac adenocarcinoma. The patient was enrolled into a clinical trial and underwent three “whole-body thermal therapy” (WBTT) sessions combined with four hypofractionated radiotherapy sessions during a ten-weeks’ time period. The medical device and corresponding treatment protocol were designed by ElmediX (ElmediX NV, Belgium). Air was injected at high speed in a treatment chamber and automatically regulated to reach and maintain a body temperature of 41.5°C for eight hours. Thermometry was ensured by temperature sensors placed in and on the patient. During four radiotherapy sessions, an external beam delivered hypofractionated doses of 6Gy on both the primary tumor and the metastatic lymph nodes. Clinical monitoring and assessment of quality of life confirmed that the WBTT sessions were well tolerated. Although burn wounds at pressure points occurred, prolonged severe adverse effects were not observed. Furthermore, the disease progression was deemed slower than the expected progression based on the literature.

Minimal complications observed with a modified surgical approach for treatment of canine anal sac neoplasia

OBJECTIVE To describe a modified approach to closed anal sacculectomy and report the short-term outcomes of dogs that underwent the procedure for treatment of neoplasia. ANIMALS 16 client-owned dogs. PROCEDURES Medical records of 1 referral hospital were reviewed to identify dogs that underwent modified closed anal sacculectomy for treatment of anal sac neoplasia between January 2018 and September 2020. Data collected included signalment, examination and diagnostic imaging findings, surgical details, intraoperative and postoperative complications, cytologic and histologic findings, adjuvant treatments, duration of follow-up, and short-term outcome. RESULTS 15 dogs had apocrine gland anal sac adenocarcinoma, and 1 had a collision tumor. No dogs had intraoperative complications; 1 dog had a minor postoperative complication (paraparesis) that resolved. The median duration of postoperative follow-up was 286 days (range, 67 to 777 days). One dog had confirmed local disease recurrence 290 days after surgery, and 1 had suspected local disease recurrence 203 days after surgery and was euthanized because of systemic disease progression. CONCLUSIONS AND CLINICAL RELEVANCE The modified closed anal sacculectomy was well tolerated in this sample of dogs, with minimal short-term complications. This study provided evidence to justify evaluation of the procedure in a larger number of dogs and assessment of the effects of procedural modifications on postoperative complication rates and time to local recurrence.

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.

Unilateral anal sacculectomy for anal sac apocrine gland adenocarcinoma with urethral involvement

The patient presented to a veterinary hospital with a month-long history of ‘scooting’ and a right-sided anal gland mass. A diagnosis of a stage 2 anal sac apocrine gland adenocarcinoma was confirmed, and the patient underwent a right-sided anal sacculectomy. There was involvement of the urethra and adherence to the rectum and a subsequent urethral incision was necessary, which was surgically repaired at the time of surgery. The patient was hospitalised for several weeks postoperatively for urinary catheter care and further nursing interventions. The patient was discharged from hospital 3 weeks after surgery once the urethra had healed sufficiently enough to enable normal micturition and subsequently made a full recovery.

Odorant-binding proteins in canine anal sac glands indicate an evolutionarily conserved role in mammalian chemical communication

Background Chemical communication is an important aspect of the behavioural ecology of a wide range of mammals. In dogs and other carnivores, anal sac glands are thought to convey information to conspecifics by secreting a pallet of small volatile molecules produced by symbiotic bacteria. Because these glands are unique to carnivores, it is unclear how their secretions relate to those of other placental mammals that make use of different tissues and secretions for chemical communication. Here we analyse the anal sac glands of domestic dogs to verify the secretion of proteins and infer their evolutionary relationship to those involved in the chemical communication of non-carnivoran mammals. Results Proteomic analysis of anal sac gland secretions of 17 dogs revealed the consistently abundant presence of three related proteins. Homology searches against online databases indicate that these proteins are evolutionary related to ‘odorant binding proteins’ (OBPs) found in a wide range of mammalian secretions and known to contribute to chemical communication. Screening of the dog’s genome sequence show that the newly discovered OBPs are encoded by a single cluster of three genes in the pseudoautosomal region of the X-chromosome. Comparative genomic screening indicates that the same locus is shared by a wide range of placental mammals and that it originated at least before the radiation of extant placental orders. Phylogenetic analyses suggest a dynamic evolution of gene duplication and loss, resulting in large gene clusters in some placental taxa and recurrent loss of this locus in others. The homology of OBPs in canid anal sac glands and those found in other mammalian secretions implies that these proteins maintained a function in chemical communication throughout mammalian evolutionary history by multiple shifts in expression between secretory tissues involved in signal release and nasal mucosa involved in signal reception. Conclusions Our study elucidates a poorly understood part of the biology of a species that lives in close association with humans. In addition, it shows that the protein repertoire underlying chemical communication in mammals is more evolutionarily stable than the variation of involved glands and tissues would suggest.