Ectopic hepatocellular carcinoma in a dog

CASE HISTORY: A 14-year-old neutered male Bearded Collie was presented with a history of recurrent, intermittent urinary incontinence of 7 years duration. CLINICAL FINDINGS: A large, firm, non-painful mass was found in the mid-abdominal region on palpation. Ultrasonography of the mass revealed a compartmentalised structure with mixed echogenicity, and which did not appear to be associated with any of the abdominal organs. Ultrasound-guided fine needle aspirates contained several clusters of epithelial cells with cytological features of hepatocytes. At exploratory laparotomy, the mass was found in the gastrosplenic ligament within the greater omentum. PATHOLOGICAL FINDINGS AND DIAGNOSIS: Histopathologically, the mass consisted of sheets of hepatocytes, but without the characteristic hepatic architecture. The cells showed moderate variation in nuclear size and were sometimes binucleate. A diagnosis of hepatocellular carcinoma (HCC) in the mesentery was made. CLINICAL RELEVANCE: The presence of ectopic hepatic tissue has been reported rarely in man and cats, but not in the dog. Neoplastic transformation of ectopic hepatic tissue is seen in man. This is the first report of the presentation, clinical findings and treatment of a dog with ectopic HCC.     

Possible parachordoma in a dog

Abstract

CASE HISTORY: A 15-mm diameter mass developed in the S/C tissue overlying the right lateral gluteal muscle of a 6½-year-old female Flat-coated Retriever.

PATHOLOGICAL FINDINGS: Cytological preparations following aspiration of the mass were highly cellular and consisted of a population of large polygonal cells containing single to multiple nuclei, large prominent nucleoli, and intracytoplasmic vacuoles. Histologically, the neoplasm consisted of similar large cells surrounded by thick fibrous connective tissue trabeculae. The large polygonal cells reacted positively with antibodies against vimentin, low- and high-molecular-weight variants of cytokeratin (AE1/AE3), but not with antibodies to desmin or glial fibrillary acidic protein (GFAP).

DIAGNOSIS: The clinical, gross, histological and immunohistochemical findings are similar to those reported for parachordomas in humans. Neither recurrence nor metastases were noted 18 months after surgical excision of the mass.

CLINICAL RELEVANCE: This is the first reported case of a possible parachordoma in a dog, a benign tumour with cytological features of malignancy.     

Male pseudohermaphroditism in a Labrador Retriever,and a review of mammalian sexual differentiation

CASE HISTORY: An 8-month-old Labrador Retriever was referred with a history of ambiguous external genitalia.

CLINICAL FINDINGS AND TREATMENT: Clitoromegaly within apparent vulval folds, and an adjacent subcutaneous mass were noticed on external examination. An intra-abdominal testicle, with epididymis and suspected vas deferens ducts, was found during exploratory celiotomy. Incision over the subcutaneous mass revealed the accompanying testicle. Clitoridectomy was performed and an os clitoris removed. Normal juvenile testes were diagnosed on histology of the gonads. Chromosomal studies revealed a normal 78, XY male chromosomal constitution. Due to the combination of a male karyotype (78, XY), the presence of testicular tissue in the gonads, and the appearance of the external genitalia, a diagnosis of male pseudohermaphroditism (MPH) was made.

CLINICAL RELEVANCE: This case presents the first report of MPH in a Labrador Retriever, and highlights the diagnostic steps recommended when confronted with a dog with ambiguous external genitalia.     

Squamous cell carcinoma in a tuatara (Sphenodon punctatus)

CASE HISTORY: A mature male tuatara was presented with a history of recurrent cloacal prolapse.

CLINICAL AND PATHOLOGICAL FINDINGS: The prolapsed tissue included a 12 mm diameter mass, which histologically showed cords and nodules of neoplastic epithelial cells.

DIAGNOSIS: The mass was diagnosed as a squamous cell carcinoma with ulceration of the overlying stratified squamous epithelium and diffuse inflammation of the surrounding dermis.

CLINICAL RELEVANCE: This case presented a rare opportunity to investigate squamous cell carcinoma in a long-lived lower vertebrate species. Future recurrence or metastasis of the mass may add useful information to the current base of knowledge of the behaviour of malignant neoplasms in reptiles.     

Ectopic pregnancy through a caesarean scar in a ewe

CASE HISTORY: A routine ultrasonographic examination for pregnancy diagnosis in a 3-year-old ewe revealed a normal embryo located in the uterine cavity and an abnormal mass located in the abdomen. At the time of examination, the ewe was 4.5?months pregnant, but 10?months previously she had undergone a caesarean section due to dystocia.

CLINICAL FINDINGS: The abnormal mass (12?cm × 8?cm) was located outside the uterine cavity; it was anechoic at the periphery, and in the centre there was an echogenic embryo-like structure. Exploratory laparotomy was performed, which revealed an ectopic pregnancy through the caesarean scar.

TREATMENT: The ectopic foetus was excised and the caesarean scar was repaired. The ewe made a complete recovery and the intrauterine pregnancy was completed to full-term, resulting in the birth of a healthy female lamb 35?days after the removal of the ectopic foetus.

CLINICAL RELEVANCE: Ectopic pregnancies have previously been described in ewes. As far as the authors are aware, this is the first report of an ectopic pregnancy through a caesarean scar in sheep or any other farm animal species.     

Nasal infection with Scedosporium apiospermum in a dog

CASE HISTORY: A 2-year-old female Siberian Husky was presented with a 6-month history of sneezing and mucous discharge from the right nostril.

CLINICAL FINDINGS: Reduced airflow through the right nostril was evident. Radiographs showed subtle loss of detail of turbinates within the right nasal chamber. Rhinoscopy revealed swollen and erythematous turbinates and a white mass within the caudal aspect of the right nasal cavity. Histopathologically, there was a heavy mixed inflammatory infiltrate in the submus- cosa of the right turbinate, and the presence of fungal hyphae and spores in the white mass. A heavy growth of Scedosporium apiospermum was cultured from the mass.

DIAGNOSIS: Chronic rhinitis of the right nasal cavity and infection with S. apiospermum.

CLINICAL RELEVANCE: This is the first reported case of S. apiospermum isolated from the nasal cavity of a dog in New Zealand. Fungal culture is necessary to differentiate this fungus from Aspergillus spp.     

Necrotising fasciitis associated with Escherichia coli in a dog

CASE HISTORY: Lameness and limb pain associated with a laceration in the inner thigh of a Border Collie dog progressed over 4 days to extensive necrosis of the full-thickness of skin and subcutaneous (S/C) tissue. A successful outcome was achieved using surgical debridement and intensive supportive care, followed by limited local closure, axial pattern flap development, and free skin grafting.

CLINICAL FINDINGS: Clinical findings included severe pain, depression, pyrexia and hypoalbuminaemia, and full-thickness loss of skin from the caudal thigh to the hock. Histopathologically, debrided tissue showed extensive necrosis of the dermis, adipose and muscle tissues, and the presence of numerous Gram-negative rods. Escherichia coli was cultured from deep tissue samples.

DIAGNOSIS: Necrotising fasciitis (NF) associated with E. coli infection.

CLINICAL RELEVANCE: NF associated with E. coli has not been previously reported in dogs. The importance of early diagnosis and surgical debridement is noted and the relevant medical literature is reviewed.     

Pancreatic cyst in a cat

CASE HISTORY: A 5-year-old neutered male Cornish Rex cat was presented for evaluation with a history of vomiting over the previous 5 days.

CLINICAL FINDINGS: An abdominal mass was palpated, which was shown to be cystic by ultrasound examination. Exploratory surgery revealed this to be associated with the pancreas and it was duly resected. Histopathology was performed on the cystic mass.

DIAGNOSIS: Pancreatic cyst with associated chronic active infl ammation.

CLINICAL RELEVANCE: This is the first report of a true pancreatic cyst in a cat.     

Canine gastrinoma: A case study and literature review of therapeutic options

CASE HISTORY: A 6.2 kg, 8-year-old, spayed female Australian Terrier was presented with weight loss, inappetence, lethargy and a 2-day history of intermittent vomiting.

CLINICAL FINDINGS: The dog had cranial abdominal pain and there was melaena present on digital rectal examination. Haematology revealed a marked, acute leucogram.

DIAGNOSIS AND TREATMENT: Fasting serum gastrin levels were markedly elevated and gastrinoma was suspected. Treatment was initiated with omeprazole, ranitidine and sucralfate. The dog remained clinically normal for 26 months, at which time exploratory surgery was undertaken and the dog subsequently euthanised due to extensive metastases. Histopathology and immunocytochemistry confirmed the diagnosis of metastatic gastrinoma.

CLINICAL RELEVANCE: This is a rare condition infrequently reported. Although the number of cases treated with omeprazole are too few to draw firm conclusions, it would appear that proton pump inhibitors are useful and should be considered for cases of gastrinoma managed medically. Long-term prognosis is poor, and survival times range from 1 to 147 weeks. Many treatment options are discussed in the medical literature though not all are feasible in veterinary patients.     

Successful treatment of a pancreatic pseudocyst by omentalisation in a dog

CASE HISTORY A 3-year-old male Labrador retriever was presented with a history of dietary indiscretion followed by vomiting and abdominal pain.

CLINICAL FINDINGS AND TREATMENT: Abdominal ultrasonography revealed the presence of a fluid-filled cystic structure in the region of the pancreas. Flocculent, dark fluid was drained from the cystic structure during exploratory celiotomy prior to resection of the lateral cystic wall. Omentum was sutured into the cystic cavity to provide drainage and enhance immune response. A jejunostomy feeding tube was placed. Post-surgical care consisted of antibiotic therapy. The dog was clinically normal at 1 and 7 months post-operatively and the pancreas appeared normal on final ultrasonographic examination.

CLINICAL RELEVANCE: This case describes the use of omentum to provide physiological drainage of a pancreatic pseudocyst. This surgical technique may help clinicians manage patients with this condition in the future.     

Long-term survival after combination chemotherapy for bilateral renal malignant lymphoma in a dog

CASE HISTORY: A 6-year-old, entire male Flat-coated Retriever was presented with a history of lethargy, polydipsia and seizures. Clinical chemistry had shown marked azotaemia.

CLINICAL FINDINGS AND DIAGNOSIS: Radiography and ultrasonography revealed bilateral renomegaly, and cytology of fine needle aspirates from the kidneys was diagnostic of malignant lymphoma. The dog was treated with a modified high-dose cyclophosphamide-, vincristine-, and prednisolone-based chemotherapy protocol, achieved remission, and returned to normal quality of life. Survival time was 346 days from the time of diagnosis.

CLINICAL RELEVANCE: Malignant lymphoma in the kidneys of dogs has been considered to carry a uniformly poor prognosis. Long-term remission after medical treatment has not previously been reported. The favourable outcome in this case illustrates the limitations of clinical staging in determining the outcome for individual patients.     

Abortions in sheep caused by Salmonella Brandenburg: Pathological findings

CASE HISTORY: A 7-year-old cat developed sporadic vomiting, reduced appetite, and weight loss over the previous 3 months.

CLINICAL FINDINGS: Palpation revealed a large mid-abdominal mass and the cat had marked eosinophilia. The cat progressively lost weight over the next 7 weeks when euthanasia was performed.

PATHOLOGICAL FINDINGS: Necropsy revealed a 3?cm diameter firm white intramural mass in the colon and another in the pylorus. Mesenteric and cranial mediastinal lymph nodes were firm, pale, and enlarged. Histopathological examination revealed foci of necrosis surrounded by thick dense collagen trabeculae and predominantly eosinophilic inflammation within the intestine and lymph nodes. Marked eosinophilic infiltration of the liver was also present.

DIAGNOSIS: The lesions were consistent with gastrointestinal eosinophilic sclerosing fibroplasia (FGESF).

CLINICAL RELEVANCE: This is the first report of FGESF in a New Zealand cat and the first time lesions of FGESF have been observed in extra-abdominal tissues. Intestinal neoplasia can be clinically identical to FGESF and histopathology is required for differentiation. Evidence suggests that FGESF has a more favourable prognosis than intestinal neoplasia.     

Macrocyclic lactone toxicity due to abamectin in farm dogs without the ABCB1 gene mutation

Abstract

CASE HISTORY: A 5-year-old entire female Huntaway from a sheep and beef farm was one of four dogs that developed clinical signs including hypersalivation, depression, blindness and ataxia after the death of another dog. A 4-year-old female Huntaway farm dog from a second farm was observed to be sitting down more often than usual on the day after being fed part of a calf carcass that had been treated with an abamectin pour-on.

CLINICAL FINDINGS: The first dog was ataxic and depressed but did respond to sound. The second dog presented with an acute onset of blindness, mydriasis, absence of a menace response, hypersalivation, gait abnormalities (e.g. high stepping gait and ataxia), and depression. Other presenting signs included muscle tremors, dehydration and difficulty eating. No abnormalities were detected from routine haematology and biochemistry. Analysis of samples of plasma from both dogs revealed concentrations of abamectin of 0.149 mg/L and 0.260 mg/L for the first and second dogs, respectively. Buccal swabs taken from the first dog for DNA testing for the ABCB1 gene mutation, gave a negative result.

DIAGNOSIS: In addition to the presenting signs which suggested a toxicosis, both dogs had measurable concentrations of abamectin in plasma confirming exposure.

CLINICAL RELEVANCE: Farm dogs exposed to concentrated pour-on products containing abamectin have been poisoned and recover or die. The product labels do not carry any warnings as to the risk of poisoning to dogs. This paper discusses two incidents affecting six farm dogs, but the authors are aware of more toxicoses in farm dogs exposed to abamectin.     

Cloacal papillomatosis in the absence of herpesvirus and papillomavirus in a sulphur-crested cockatoo (Cacatua galerita)

CASE HISTORY A 21-year-old male sulphur-crested cockatoo (Cacatua galerita) was presented following the sudden appearance of blood associated with the passage of faeces and urates.

CLINICAL AND PATHOLOGICAL FINDINGS: There was fresh blood-staining of the feathers around the vent. The dorsal mucosal wall of the proctodeum was erythematous and roughened in appearance. An endoscopic biopsy was performed, and histological examination revealed multiple fronds of epithelium; the mucosa varied from simple to pseudostratified columnar epithelium, with diffuse hyperplasia of goblet cells. The underlying connective tissue stroma was well vascularised and was infiltrated with mixed inflammatory cells, comprising granulocytic cells and macrophages. PCR testing for both herpesvirus and papillomavirus, using consensus primers, was negative.

DIAGNOSIS: Cloacal papillomatosis.

CLINICAL RELEVANCE: This case manifested typical clinical signs and histological lesions of cloacal papillomatosis in the absence of demonstrable herpesvirus or papillomavirus. Veterinarians need to consider this disease in the differential diagnosis of blood in the droppings of parrots and cockatoos even in countries where psittacine herpesviruses are exotic diseases.     

Extramedullary laryngeal plasmacytoma in a dog

Abstract

CASE HISTORY:?An 8-year-old, female, spayed Border Collie presented with a 3-week history of coughing, choking and haemoptysis.

CLINICAL FINDINGS:?Inspiratory stridor was evident on clinical examination. Cervical radiographs revealed a round soft-tissue mass on the dorsal aspect of the epiglottis. A laryngeal mass was evident on examination under anaesthesia, and an incisional biopsy was obtained. Histopathology revealed a dense proliferation of neoplastic round cells morphologically consistent with plasma cell origin. Immunohistochemisty results were negative for CD3 (T cell marker) and positive for CD79a (B cell marker), resulting in a diagnosis of extramedullary plasmacytoma. The patient was treated with melphalan and prednisolone; clinical signs resolved within 1 week and the mass was no longer evident on laryngoscopy after 1 month of treatment. After 6 months of chemotherapy, the laryngeal mass recurred and euthanasia was requested. There was no evidence of systemic spread on post-mortem examination.

DIAGNOSIS:?Solitary extramedullary plasmacytoma of the canine larynx.

CLINICAL RELEVANCE:?Respiratory extramedullary plasmacytomas are extremely rare with only one laryngeal and two tracheal cases previously reported. This is the first published report of a laryngeal plasmacytoma that recurred despite combination chemotherapy with melphalan and prednisolone.     

Male pseudohermaphroditism in a Labrador Retriever, and a review of mammalian sexual differentiation

CASE HISTORY: An 8-month-old Labrador Retriever was referred with a history of ambiguous external genitalia. CLINICAL FINDINGS AND TREATMENT: Clitoromegaly within apparent vulval folds, and an adjacent subcutaneous mass were noticed on external examination. An intra-abdominal testicle, with epididymis and suspected vas deferens ducts, was found during exploratory celiotomy. Incision over the subcutaneous mass revealed the accompanying testicle. Clitoridectomy was performed and an os clitoris removed. Normal juvenile testes were diagnosed on histology of the gonads. Chromosomal studies revealed a normal 78, XY male chromosomal constitution. Due to the combination of a male karyotype (78, XY), the presence of testicular tissue in the gonads, and the appearance of the external genitalia, a diagnosis of male pseudohermaphroditism (MPH) was made. CLINICAL RELEVANCE: This case presents the first report of MPH in a Labrador Retriever, and highlights the diagnostic steps recommended when confronted with a dog with ambiguous external genitalia.     

Ventricular pneumocephalus and septic meningoencephalitis secondary to dorsal rhinotomy and nasal polypectomy in a dog

CASE DESCRIPTION: A 4-year-old sexually intact female French Bulldog was evaluated because of lethargy, anorexia, and chronic rhinitis-sinusitis. The dog had nasal discharge of 18 months' duration; dorsal rhinotomies were performed 3 months and 2 weeks prior to referral. CLINICAL FINDINGS: On initial evaluation, intraventricular pneumocephalus and sinusitis were diagnosed; CSF analysis revealed high total protein concentration and mononuclear pleocytosis. The dog's condition improved with treatment. Two weeks after discharge, it was treated by a local veterinarian because of upper airway obstruction; 3 days later, the dog was referred because of seizures. Computed tomography revealed a large fluid-filled, left lateral ventricle and a soft tissue mass protruding through a cribriform plate defect. The mass was histologically consistent with brain tissue. Findings of clinicopathologic analyses were unremarkable. Results of cytologic examination of a CSF sample were indicative of septic, suppurative inflammation, and bacteriologic culture of CSF yielded Escherichia coli. TREATMENT AND OUTCOME: Amputation of the herniated olfactory bulb and antimicrobial treatment resolved the septic meningoencephalitis, but neurologic deficits recurred 6 weeks later. Definitive correction of the cribriform plate defect with bone and fascial grafts was attempted. Postoperative rotation of the bone graft resulted in cerebral laceration and hemorrhage, and the dog was euthanized. CLINICAL RELEVANCE: Findings suggest that following dorsal rhinotomy and nasal polypectomy surgery, the dog developed herniation of the left olfactory bulb, intra-ventricular pneumocephalus, and septic meningo-encephalitis because of a cribriform plate defect. Care must be taken to prevent rotation of bone grafts used in cribriform defect repair.     

An outbreak of avian malaria in captive yellowheads/mohua (Mohoua ochrocephala)

CASE HISTORY: Eight mohua, or yellowheads (Mohoua ochrocephala), were held in a large open aviary over the summer months of 2003–2004, following their capture for captivebreeding purposes. Two birds died of transportation trauma shortly after arrival, one became ill and died a month later, and another four died within a 2-week period in February 2004. The eighth bird also became ill at this time but survived for a year following treatment with chloroquine and doxycycline.

CLINICAL AND PATHOLOGICAL FINDINGS: The affected birds were depressed, lethargic and dyspnoeic. Necropsy of three birds showed a slightly pale and swollen liver and spleen. Impression smears of the liver of one bird revealed schizonts resembling Plasmodium spp. within the cytoplasm of many hepatocytes, which was confirmed histopathologically. Similar protozoal organisms were seen within splenic histiocytes and pulmonary endothelial cells of 5/6 birds. Electron microscopy identified these as protozoal schizonts containing merozoites of similar size and structure to those of Plasmodium spp.

DIAGNOSIS: The birds were infected with a protozoal haemoparasite resembling Plasmodium spp.; asexual stages within hepatocytes and endothelial cells of the lung and spleen were typical of this organism.

CONCLUSIONS AND CLINICAL RELEVANCE: The mohua captured from west Otago were highly susceptible to avian malaria as they came from an isolated population that was likely to be naïve and have had no previous contact with this organism. The birds were probably infected by bites from mosquitoes feeding off local populations of blackbirds subsequently found to be infected with Plasmodium spp.     

Acute hepatic failure and coagulopathy associated with xylitol ingestion in eight dogs

CASE DESCRIPTION: 8 adult dogs were evaluated for treatment of lethargy and vomiting after ingestion of xylitol, a sugar alcohol used as a sweetener in various products. CLINICAL FINDINGS: In addition to vomiting and lethargy, 5 of the dogs had widespread petechial, ecchymotic, or gastrointestinal tract hemorrhages. Common clinicopathologic findings included moderately to severely high serum activities of liver enzymes, hyperbilirubinemia, hypoglycemia, hyperphosphatemia, prolonged clotting times, and thrombocytopenia. Necropsies were performed on 3 dogs and severe hepatic necrosis was found in 2. In the third dog, histologic examination revealed severe hepatocyte loss or atrophy with lobular collapse. TREATMENT AND OUTCOME: Treatments varied among dogs and included IV administration of fluids; plasma transfusions; and, if indicated, administration of dextrose. Three dogs were euthanatized, 2 dogs died, 2 dogs made a complete recovery, and 1 dog was recovering but was lost to follow-up. CLINICAL RELEVANCE: Although xylitol causes hypoglycemia in dogs, hepatic failure after ingestion has not previously been reported. Because an increasing number of consumer products contain xylitol, clinicians should be aware that ingestion of xylitol can have serious, life-threatening effects.