Anal sacculiths may be an incidental finding in dogs.

Mineral-attenuating material is occasionally seen in the anal sacs of dogs during abdominal CT studies. This retrospective, descriptive study was performed to estimate the prevalence and CT appearance of this mineral-attenuating material. A total of 357 abdominal CTs were reviewed retrospectively. The mineral-attenuating material was most easily identifiable using the brain window setting (window width: 120 HU; window level: 40 HU). In the current study, the prevalence of mineral-attenuating material in the anal sacs was 7.6% (95% confidence interval, 5.0-10.8%) with 48.1% bilateral involvement and equal distribution in the right and left in dogs with unilateral involvement. Successful collection and material analysis were performed in three dogs. The material was determined to be 100% dried blood, 100% waxy matter, and a "small amount of fat enmeshed in unidentified noncrystallined material." Given the CT appearance and the Hounsfield unit of these mineral-attenuating material within the anal sacs, the term "anal sacculiths" is proposed. All dogs with anal sacculiths within this study population did not have any reported disease of the anal sacs.

Sentinel lymph node mapping of the canine anal sac using lymphoscintigraphy: A pilot study.

Sentinel lymph node mapping and biopsy are important parts of oncologic staging in human medicine. Sentinel lymph node mapping enables identification of the first lymph node to receive lymphatic drainage while avoiding unnecessary lymph node dissection. Anal sac adenocarcinoma is the most common malignant neoplasm of the canine perineal area. For dogs with anal sac adenocarcinoma, lympadenectomy and metastasis to the iliosacral lymphocentrum are negative prognostics indicators. The objectives of this prospective, two by two, crossover pilot study were to establish the feasibility of lymphoscintigraphy using Technetium-99 sulfur colloid of the canine anal sac of healthy dogs, compare two injection techniques, and the time for identification of sentinel lymph nodes using each technique. We hypothesized that both intramural and perimural injections of the canine anal sac would identify similar sentinel lymph node drainage. The sentinel lymph node was identified in all dogs using either technique. Intramural injection of the canine anal sac showed radiopharmaceutical uptake faster than perimural injection technique (P = 0.040). There was concordance between intramual and perimural techniques for the sentinel lymph node identified in 50% of cases. A sacral lymph node was identified as sentinel in three of eight dogs (37.5%). Lymphoscintigraphy of the canine anal sac is safe and feasible in normal dogs; however, the method of injection technique seems to have a significant effect on the sentinel lymph node identified.

INDIRECT COMPUTED TOMOGRAPHIC LYMPHOGRAPHY FOR ILIOSACRAL LYMPHATIC MAPPING IN A COHORT OF DOGS WITH ANAL SAC GLAND ADENOCARCINOMA: TECHNIQUE DESCRIPTION.

Sentinel lymph node mapping can help to direct surgical oncologic staging and metastatic disease detection in patients with complex lymphatic pathways. We hypothesized that indirect computed tomographic lymphography (ICTL) with a water-soluble iodinated contrast agent would successfully map lymphatic pathways of the iliosacral lymphatic center in dogs with anal sac gland carcinoma, providing a potential preoperative method for iliosacral sentinel lymph node identification in dogs. Thirteen adult dogs diagnosed with anal sac gland carcinoma were enrolled in this prospective, pilot study, and ICTL was performed via peritumoral contrast injection with serial caudal abdominal computed tomography scans for iliosacral sentinel lymph node identification. Technical and descriptive details for ICTL were recorded, including patient positioning, total contrast injection volume, timing of contrast visualization, and sentinel lymph nodes and lymphatic pathways identified. Indirect CT lymphography identified lymphatic pathways and sentinel lymph nodes in 12/13 cases (92%). Identified sentinel lymph nodes were ipsilateral to the anal sac gland carcinoma in 8/12 and contralateral to the anal sac gland carcinoma in 4/12 cases. Sacral, internal iliac, and medial iliac lymph nodes were identified as sentinel lymph nodes, and patterns were widely variable. Patient positioning and timing of imaging may impact successful sentinel lymph node identification. Positioning in supported sternal recumbency is recommended. Results indicate that ICTL may be a feasible technique for sentinel lymph node identification in dogs with anal sac gland carcinoma and offer preliminary data to drive further investigation of iliosacral lymphatic metastatic patterns using ICTL and sentinel lymph node biopsy.

Association between total hypercalcaemia and iliosacral lymph node metastasis in dogs diagnosed with anal sac adenocarcinoma using abdominal ultrasonography.

BACKGROUND: Anal sac adenocarcinoma (ASACA) in dogs is a malignant perianal tumour that often metastasizes to the iliosacral lymph nodes. Additionally, this tumour can be associated with hypercalcemia of malignancy. To date, no study has looked at the association between increased blood calcium levels and suspected or confirmed lymph node metastasis as a primary objective. OBJECTIVE: The objective of this study was to determine if increased total serum calcium level is associated with iliosacral lymph node metastasis in dogs diagnosed with ASACA. METHODS: Medical records of a single referral hospital were searched to identify dogs examined between 2011 and 2021 that had a diagnosis of ASACA via cytology or histopathology. Only dogs that had serum total calcium recorded and abdominal ultrasound were included in the study. All images were reviewed by a board-certified radiologist blinded to any patient identifiers. RESULTS: Of the 58 dogs, 33% (19/58) had total hypercalcaemia, and of these, 68% had confirmed or suspected iliosacral lymph node metastasis. Total hypercalcaemia was significantly associated with confirmed or suspected iliosacral lymph node metastasis (p < 0.01). However, 46% (11/24) of dogs with confirmed or suspected iliosacral lymph node metastasis were normocalcaemic. CONCLUSIONS: Based on these results, it is suggested that while the presence of total hypercalcaemia may increase the likelihood of concurrent lymph node metastasis, total hypercalcaemia alone cannot be used as a screening tool for lymph node metastasis. Dogs diagnosed with ASACA should undergo full staging regardless of total serum calcium values.

Computed tomographic staging of dogs with anal sac adenocarcinoma.

OBJECTIVES: To describe the CT appearance of anal sac adenocarcinoma lesions in a population of dogs including the relations between primary tumour, and locoregional and distant metastasis. MATERIALS AND METHODS: Retrospective review of dogs with confirmed anal sac adenocarcinoma and available CT images of the thorax, abdomen and pelvis. RESULTS: A population of 70 dogs were included in the study. No association was found between anal sac mass size and presence or absence of iliosacral lymph node enlargement. The prevalence of local metastatic disease characterised by iliosacral lymphadenomegaly in this study was 71%, with pulmonary metastases identified in 11% of cases. There were no cases of distant pulmonary metastasis without concurrent locoregional lymphadenomegaly. CLINICAL SIGNIFICANCE: In our population of dogs local metastatic spread of anal sac adenocarcinoma was common, with a relatively low prevalence of pulmonary metastasis. The study demonstrates the importance of thorough rectal examination and/or imaging to assess the iliosacral lymph centre in this disease irrespective of the size of the anal sac mass.

Optical coherence tomography imaging of excised canine apocrine gland anal sac adenocarcinoma tumours.

Optical coherence tomography (OCT) is an optical imaging modality that has been investigated for real-time surgical margin evaluation in human breast cancer patients. Previous veterinary OCT studies have been limited to surgical margin imaging for soft tissue sarcoma (STS) tumours. To the authors knowledge, OCT has never been used to characterize or evaluate other types of neoplasia in dogs. The goal of this study was to characterize the OCT imaging appearance of apocrine gland anal sac adenocarcinoma (AGASACA) in excised ex vivo specimens from five client-owned dogs. All excised tissue surgical margins were imaged using a clinical spectral domain OCT system and two to four areas suspicious for incomplete surgical margins were selected. These areas were inked and sections were trimmed for histopathology. This enabled OCT imaging from each area of interest to be compared with corresponding H&E stained histology imaging from the same location. OCT was able to identify the presence of AGASACA at or within 1 mm of the surgical margin in all areas of interest. AGASACA, similar to the previously described canine STS, generated a dense, highly scattering image without any specific textural architecture. This study was able to validate the ability of OCT to accurately identify another type of tumour presence at or close to the surgical margin in the dog. Further study is needed to assess OCT accuracy at identifying other tumour types in dogs to understand its potential clinical applications.

Intraglandular injection of antibiotics for the treatment of vesicular adenitis in bulls.

Two experiments were designed to determine the efficacy of intraglandular antibiotic treatment in beef bulls. Experiment 1 was designed to evaluate the glandular tissue reaction to intraglandular antibiotic treatment. Experiment 2 was conducted to determine the efficacy intraglandular injection of antibiotics for the treatment of naturally occurring cases of vesicular adenitis. Healthy beef bulls (n=15), 2 and 3 years of age, were randomly allocated to three equal treatment groups to receive 10% of the daily recommended parenteral dose of penicillin, ceftiofur, or oxytetracycline in a volume of 6 mL injected directly into one of the vesicular glands. Ultrasonography was performed before, immediately after, and at 24, 48 and 168 h after intraglandular injection. The size and hardness of vesicular glands injected with oxytetracycline was greater (P<0.01) than those injected with ceftiofur. Ultrasonographic pixel intensity increased (P<0.01) after treatment with antibiotics, especially after treatment with oxytetracycline or penicillin. In Experiment 2, yearling beef bulls with clinical vesicular adenitis (n=14) were referred to the Western College of Veterinary Medicine for treatment. Eight bulls had unilateral and six had bilateral vesicular adenitis. The most common isolate was Arcanobacterium pyogenes. Corynebacterium pseudotuberculosis was isolated from one bull. Bulls were subjected to rectal palpation and ultrasonography of the vesicular glands, semen collection by electroejaculation, and intraglandular treatment with ceftiofur (n=13) and if necessary, a second intraglandular treatment of penicillin (n=6). One bull was treated only with an initial intraglandular injection of penicillin. Bulls were evaluated once a week over 6 weeks by palpation of the glands, and evaluation of semen. All bulls recovered from vesicular adenitis after 3-6 weeks. There was a difference in the amount of pus (P=0.042), leukocytes (P<0.001) and blood (P=0.003) present in ejaculates from before treatment to 3 weeks after treatment. Pixel intensities in ultrasonographic images of healthy or affected vesicular glands, whether treated or untreated, did not change over time. Intraglandular injection of ceftiofur in yearling bulls via the ischiorectal fossa was effective for treating vesicular adenitis.

Ultrasound and computed tomography of the iliosacral lymphatic centre in dogs with anal sac gland carcinoma.

In this prospective study, we hypothesized that computed tomography (CT) would identify more normal and abnormal iliosacral lymph nodes (LNs) than abdominal ultrasound in dogs with anal sac gland carcinoma (ASGC). Twelve client-owned dogs with ASGC but without distant metastasis were enrolled. Abdominal ultrasound and contrast-enhanced CT scans of the abdomen were obtained. Iliosacral LNs were counted and assessed for location, laterality and size. Significantly (P < 0.00001) more iliosacral LNs were identified with CT (61) than ultrasound (30), including significantly (P = 0.00012) more medial iliac LNs with CT (33) than ultrasound (19). There was no difference in number of internal iliac LNs identified with CT versus ultrasound. Significantly (P = 0.000061) more sacral LNs were identified with CT (15) than ultrasound (0). Ultrasound identified slightly more (7) abnormal iliosacral LNs than CT (5). Contrast CT was able to identify more normal but not more abnormal LNs than ultrasound.

Diagnostic imaging features of normal anal sacs in dogs and cats.

This study was conducted to provide normal reference features for canine and feline anal sacs using ultrasound, low-field magnetic resonance imaging (MRI) and radiograph contrast as diagnostic imaging tools. A total of ten clinically normal beagle dogs and eight clinically normally cats were included. General radiography with contrast, ultrasonography and low-field MRI scans were performed. The visualization of anal sacs, which are located at distinct sites in dogs and cats, is possible with a contrast study on radiography. Most surfaces of the anal sacs tissue, occasionally appearing as a hyperechoic thin line, were surrounded by the hypoechoic external sphincter muscle on ultrasonography. The normal anal sac contents of dogs and cats had variable echogenicity. Signals of anal sac contents on low-field MRI varied in cats and dogs, and contrast medium using T1-weighted images enhanced the anal sac walls more obviously than that on ultrasonography. In conclusion, this study provides the normal features of anal sacs from dogs and cats on diagnostic imaging. Further studies including anal sac evaluation are expected to investigate disease conditions.

Utility of Computed Tomography versus Abdominal Ultrasound Examination to Identify Iliosacral Lymphadenomegaly in Dogs with Apocrine Gland Adenocarcinoma of the Anal Sac.

BACKGROUND: Apocrine gland adenocarcinoma of the anal sac (AGAAS) is associated with high rates of iliosacral lymph node metastasis, which may influence treatment and prognosis. Magnetic resonance imaging (MRI) recently has been shown to be more sensitive than abdominal ultrasound examination (AUS) in affected patients. OBJECTIVE: To compare the rate of detection of iliosacral lymphadenomegaly between AUS and computed tomography (CT) in dogs with AGAAS. ANIMALS: Cohort A: A total of 30 presumed normal dogs. Cohort B: A total of 20 dogs with AGAAS that underwent AUS and CT. METHODS: Using cohort A, mean normalized lymph node : aorta (LN : AO) ratios were established for medial iliac, internal iliac, and sacral lymph nodes. The CT images in cohort B then were reviewed retrospectively and considered enlarged if their LN : AO ratio measured 2 standard deviations above the mean normalized ratio for that particular node in cohort A. Classification and visibility of lymph nodes identified on AUS were compared to corresponding measurements obtained on CT. RESULTS: Computed tomography identified lymphadenomegaly in 13 of 20 AGAAS dogs. Of these 13 dogs, AUS correctly identified and detected all enlarged nodes in only 30.8%, and either misidentified or failed to detect additional enlarged nodes in the remaining dogs. Despite limitations in identifying enlargement in all affected lymph nodes, AUS identified at least 1 enlarged node in 100% of affected dogs. CONCLUSION AND CLINICAL IMPORTANCE: Abdominal ultrasound examination is an effective screening test for lymphadenomegaly in dogs with AGAAS, but CT should be considered in any patient in which an additional metastatic site would impact therapeutic planning.

Comparison of abdominal ultrasound and magnetic resonance imaging for detection of abdominal lymphadenopathy in dogs with metastatic apocrine gland adenocarcinoma of the anal sac.

Imaging studies in humans with anal and rectal cancer indicate that magnetic resonance imaging (MRI) is a more sensitive technique than abdominal ultrasound (AUS) for the detection of abdominal lymphadenopathy. The purpose of this retrospective study was to directly compare the efficacy of these two techniques in detecting abdominal lymphadenopathy in dogs with apocrine gland adenocarcinoma of the anal sac (AGAAS). Six dogs with histologically confirmed AGAAS and histopathologic confirmation of metastasis to abdominal lymph nodes (LNs) had AUS and abdominal MRI. AUS identified lymphadenopathy in two of six dogs, whereas MRI identified lymphadenopathy in all the six dogs. Lymphadenopathy was predominantly sacral in location, with involvement of the medial iliac and hypogastric LNs in only two cases. These data suggest that MRI is more sensitive than AUS for detecting sacral abdominal lymphadenopathy in dogs with AGAAS. As such, MRI could be considered in any patient with AGAAS for initial staging of this disease.

Ultrasonography of the medial iliac lymph nodes in the dog.

Sixty-one medial iliac lymph nodes of 38 different dogs (eight with adenocarcinoma of the apocrine glands of the anal sac, 13 with multicentric lymphoma, six with multicentric lymphoma but in clinical remission, and 11 control dogs) were evaluated to assess the ability of ultrasound to identify and interrogate these lymph nodes across the different groups and to differentiate these groups using different sonographic parameters. Ultrasound proved to be useful to assess canine medial iliac lymph nodes. An increase in size or number of detected lymph nodes or finding rounder or heterogeneous lymph nodes could differentiate lymph nodes of dogs of the control group from lymph nodes of dogs with lymphoma or an adenocarcinoma of the apocrine glands of the anal sac. Subcategories of malignancy could not be differentiated. More studies need to be performed, both with patients with reactive lymph nodes and also focusing on other canine superficial lymph nodes, before generalizing the results of this study to other areas or diseases.