Cytologically atypical anal sac adenocarcinoma in a dog

A 10-year-old intact female Shetland Sheepdog with tenesmus had a subcutaneous mass at the left ventral aspect of the anus. On cytologic examination, 2 types of cells were observed. Most of the cells were oval to polygonal and had elliptical or elongate nuclei and a moderate amount of pale to basophilic cytoplasm. The remaining cells had round to oval nuclei and pale to basophilic cytoplasm. Cells of both types were loosely adhered to each other and were arranged in rosette-like structures. Both neoplastic cell types had fine homogenous chromatin and either a small indistinct nucleolus or no visible nucleolus. Mild anisokaryosis and anisocytosis were observed. Histologically, the mass consists of glandular structures formed by cuboidal cells admixed with bundles of spindle cells. Eosinophilic PAS- and Alcian blue-positive secretory material was found in the center of some glandular structures. Both neoplastic cell types had positive staining with paradoxical concanavalin A and expressed cytokeratin, but not vimentin, S-100, α-smooth muscle actin, or desmin. Based on location and histologic and immunohistochemical features, the final diagnosis was adenocarcinoma of the apocrine gland of the anal sac, which should be included as a cytologic differential diagnosis when spindle cells and typical epithelial cells are observed in masses in the region of the anal sac of dogs.     

Surgery of metastatic anal sac adenocarcinoma in five dogs

OBJECTIVE: To identify survival and morbidity information after surgery for metastases from apocrine gland anal sac adenocarcinomas (AGACA). STUDY DESIGN: Retrospective study. ANIMALS: Five dogs with AGACA. METHODS: Medical records of dogs that had surgery for treatment of metastatic AGACA between 1993 and 2003 were reviewed. Criteria for inclusion required that dogs had lymphadenectomy, with or without further debulking, as part of their treatment for metastatic AGACA and that the tissue was histologically confirmed as consistent with the primary AGACA. Signalment, history, physical examination findings, clinicopathologic data, imaging findings, surgical complications, number of surgeries, survival times, and cause of death were recorded. All dogs had a complete blood count, serum biochemical profile, serum electrolytes, 3-projection thoracic radiographs, abdominal radiographs and/or abdominal ultrasonography, and histologic confirmation of metastatic AGACA invading the regional lymph nodes and caudal abdomen. RESULTS: No surgical complications occurred. Three dogs were euthanatized; median survival, 20.6 months. One dog was alive for 19 months postoperatively. One dog had 5 sequential surgical procedures: 1 iliac lymphadenectomy and 4 debulking procedures of metastatic neoplastic tissue around and dorsal to the iliac vessels extending into the pelvic cavity, and was alive 54 months after initial surgery. CONCLUSION: Dogs with anal sac adenocarcinoma metastases to the iliac lymph nodes can experience long-term survival after surgical excision of the metastatic lesion. CLINICAL RELEVANCE: Lymphadenectomy may afford long-term survival to patients with metastatic anal sac adenocarcinoma.     

Metastatic anal sac adenocarcinoma in a dog presenting for acute paralysis

A 4-year old, female spayed terrier was referred for hind end paresis that rapidly progressed to paralysis. Spinal radiographs revealed vertebral collapse and bony lysis. Myelography confirmed spinal cord compression and surgical exploration found an extradural soft tissue mass. Metastatic anal sac adenocarcinoma was diagnosed at postmortem examination.     

Hypocalcemia in a dog

A case of hypocalcemia was presented with a concurrent hyperphosphatemia. Normal renal function tests excluded primary renal insufficiency. The diet was thought to contain a normal ratio of calcium and phosphorus and, therefore, nutritional secondary hyperparathyroidism was not considered. The radiographs showed normal bone density and the dog was not lame. Concentrations of immunoreactive parathyroid hormone were measured in an attempt to classify the etiology. The dog was successfully managed with calcium supplementation and vitamin D(3) or oral calcium alone.     

Functional metastatic parathyroid adenocarcinoma in a dog

A 12-year-old dachshund dog was presented for persistent hypercalcemia and hyperparathyroidism despite bilateral parathyroidectomy. Magnetic resonance imaging of the head, neck, and cranial mediastinum identified an increased number of cranial mediastinal lymph nodes with heterogeneous signal intensity. Hypercalcemia and hyperparathyroidism resolved after surgery to remove multiple cranial mediastinal lymph nodes, one of which contained presumed metastatic parathyroid tissue.     

Localised radiotherapy for a ferret with possible anal sac apocrine adenocarcinoma

A seven-year-old, neutered male ferret was referred to our hospital with two perianal masses (2.4x3.0 and 2.4x3.5 cm, respectively) that had recurred after initial surgical excision. Complete resection of the masses was impossible as there was deep invasion along the rectum. On histopathology, the masses were diagnosed as apocrine adenocarcinoma possibly of anal gland origin based on tumour location. There was marked response to localised radiotherapy using an orthovoltage unit at 4 Gy, twice weekly. No visible mass was detectable after six doses of radiation. However, at that time, pleural effusion was diagnosed and radiotherapy was discontinued. Cytology of a sample of the pleural effusion suggested mesothelioma, and no obvious pulmonary metastasis of anal sac adenocarcinoma were identified on thoracic radiography. The ferret died at home on day 71 after the first admission.     

Omentalization of cystic sublumbar lymph node metastases for long-term palliation of tenesmus and dysuria in a dog with anal sac adenocarcinoma.

A 13-year-old castrated male Bassett Hound was examined because of a 2-week history of severe constipation and tenesmus. Radiography revealed a large cystic mass in the caudal portion of the abdomen that was compressing the urethra and obstructing the pelvic canal. A small perianal mass was also noticed in the region of the left anal sac. Exploratory surgery was performed, but the mass was deemed unresectable. Instead, the mass was incised, drained, and omentalized in an attempt to establish continuous drainage after surgery. Cytologic evaluation of the perianal mass was consistent with a diagnosis of anal sac adenocarcinoma. Histologic evaluation of the abdominal mass revealed it was a lymph node effaced by adenocarcinoma. Despite the poor prognosis for anal sac adenocarcinoma with metastatic spread to the sublumbar lymph nodes, tenesmus and dysuria in this dog remained palliated until the dog's death 18 months after surgery. Omentalization was successful in providing a continuous method of fluid drainage for this cystopapillary abdominal tumor.     

Anal sac gland adenocarcinoma in the dog: 14 cases

Anal sac gland adenocarcinomas were identified in 14 dogs, 11 of which were female. The majority of the dogs were over 9 years old. Recurrence and metastasis to regional lymph nodes were common. Pseudo-hyper-parathyroidism may be seen in association with this tumour.     

Management of pleural effusion secondary to metastatic adenocarcinoma in a dog

A 4-year-old spayed Collie-type dog was evaluated for pleural effusion secondary to metastatic adenocarcinoma with no identifiable primary tumor. For 48 weeks, chemotherapy and thoracentesis palliated clinical signs associated with pleural effusion. At week 49, 5 mCi of chronic phosphate P32 (32P) suspension was injected into the right pleural space. Pleural effusion was not detected for 14 weeks after 32P administration (week 63). In week 64, 32P suspension was readministered by injecting 7.5 mCi into the right hemithorax and 2.5 mCi into the left. Pleural effusion was again detected 3 weeks later (week 67), and the dog was treated with additional chemotherapy. Death, at week 72, was caused by disseminated intravascular coagulopathy.     

Postoperative radiotherapy and mitoxantrone for anal sac adenocarcinoma in the dog: 15 cases (1991–2001)

The medical records of 15 dogs with anal sac adenocarcinoma (ASAC) treated with concurrent curative‐intent radiotherapy and mitoxantrone (MX) after surgical removal of the primary tumour were reviewed retrospectively. Radiation was prescribed at 15 daily fractions of 3.2 Gy for a total dose of 48 Gy. MX was given intravenously at a dosage of 5 mg m^?2 every 3 weeks for five treatment sessions. Twelve dogs received pelvic irradiation to include the regional lymph nodes (LNs) and three received radiation only to the perineum. At the time of diagnosis, four dogs were hypercalcaemic and seven dogs presented with regional LN metastasis. All the dogs with regional LN metastasis received pelvic irradiation, and in three cases, metastatic LNs were treated in the macroscopic disease setting. The median event‐free survival was 287 days, and the median overall survival was 956 days. Acute and chronic radiation complications were common and non‐life threatening, although chronic complications contributed to the decision to euthanize two dogs. The results observed in this retrospective analysis compare favourably with cases of ASAC in the literature related to treatment with surgery and/or chemotherapy.     

Bilateral pyelonephritis and hydroureter associated with metastatic adenocarcinoma in a dog

Metastatic adenocarcinoma, involving the trigone of the urinary bladder, resulted in bilateral pyelonephritis and hydroureter in an aged dog. Salient physical examination and clinicopathologic findings included bacterial urinary tract infection, renal pain response to abdominal palpation, and the observation of WBC casts in urine sediment. A good response to antimicrobial drug administration was observed initially; however, the dog later was euthanatized because of progressive renal disease. Necropsy revealed extensive peritoneal carcinomatosis with metastatic lesions causing occlusion of both ureters. Ostensibly, metastatic carcinoma involving the trigone resulted in urine stasis and enhanced the development of renal infection and hydroureter.     

Transient tricuspid valve regurgitation following surgical treatment of cor triatriatum dexter in a dog

Echocardiographically documented tricuspid valve regurgitation appeared immediately after surgical treatment of cor triatriatum dexter in a two-month-old rottweiler. Medical treatment was instituted with benazepril, spironolactone and furosemide. Pimobendan was added after five months, and all treatment was discontinued two months later when clinical signs of ascites and hepatomegaly had resolved and tricuspid valve regurgitation was markedly reduced on echocardiography. To the authors' knowledge, this is the first report describing the development and spontaneous improvement of haemodynamically significant tricuspid valve regurgitation following surgical treatment of cor triatriatum dexter in a dog. It is hypothesised that the increase in right atrial volume and pressure following cor triatriatum dexter repair and transient ischaemia of papillary muscles led to dilatation of the right atrioventricular annulus and subsequent severe tricuspid valve regurgitation in the face of an anatomically normal valve. Time and pharmacological preload reduction as well as normalisation of right atrial inflow and subsequent cardiac remodelling substantially reduced tricuspid valve regurgitation and eliminated clinical signs of heart failure. It is also possible that heart recovery has been spontaneous.     

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.