Tubulopapillary carcinoma with spindle cell metaplasia of the mammary gland in a cat

Sarcomatous proliferation of spindle cells was present in the mammary gland and many metastatic sites in a 10-year-old female domestic cat with tubulopapillary carcinoma in the mammary gland. Transition from neoplastic tubular structures to spindle cells in the primary site and fascicular proliferation of the spindle cells with or without coexistance of tubulopapillary carcinoma in the primary and metastatic sites were observed. Most of spindle cells were positive for cytokeratin CAM5.2 as well as the normal luminal epithelium but not the myoepithelium. From these results, this case was diagnosed as tubulopapillary carcinoma with spindle cell metaplasia and it was clarified that neoplastic luminal epithelial cells can transform to sarcomatous appearence.     

Orbital neoplasia with enophthalmos in a cat

A 9-year-old cat was evaluated for left-sided enophthalmos and protrusion of the third eyelid. A primary orbital fibrosarcoma was diagnosed. During the orbital exploration, normal periorbital fascia could not be identified in the lateral and ventral region, thus accounting for the enophthalmos.     

Pulmonary squamous cell carcinoma with multiple digital metastases in a cat

A 14-year-old domestic shorthaired cat was presented because of swelling of the digits and lameness. A solitary lung mass was observed on thoracic radiographs. Clinical and pathological evaluation confirmed a primary pulmonary squamous cell carcinoma metastatic to a single digit on each foot. Other metastatic lesions were present in the left popliteal lymph node and in the left iliac vein.     

Prostatic abscess in a neutered cat

A 6-year-old, male castrated domestic shorthair cat was presented for evaluation of lethargy, vomiting, anorexia, and constipation. Physical examination revealed an elevated body temperature and an extramural colonic mass. Abdominal ultrasonography demonstrated a hypoechoic mass measuring 2.2 cm in maximum dimension immediately caudal to the bladder. Cytological evaluation of a fine-needle aspirate confirmed the mass was a prostatic abscess. Abdominal celiotomy and prostatic omentalization were successful in resolving clinical abnormalities. Feline prostatic abscessation is a rare condition that has not been previously reported and may have a good outcome if treated early and appropriately.     

Paraneoplastic leukocytosis with mature neutrophilia in a cat with pulmonary squamous cell carcinoma

A 13-year old cat had 3-day duration of vomiting, lethargy, and anorexia. A complete blood count revealed a severe neutrophilia (126.9 x 10(3) cells/microl). Thoracic radiographs demonstrated a large solitary lung mass. A bone marrow aspirate documented myeloid hyperplasia. A left intercostal thoracotomy was performed and left cranial and caudal lung lobectomies were performed in order to remove the mass in its entirety. Histological diagnosis was squamous cell carcinoma of the lung. Following surgery, the severe neutrophilia began to decrease. It was in the normal range approximately 6 weeks postoperatively. The presence of a primary lung tumor combined with a mature neutrophilia with resolution following surgical resection suggests a paraneoplastic syndrome.     

Oral and peripheral vestibular signs in a cat with squamous cell carcinoma

A 13-year-old female, spayed cat had oral and vestibular signs resulting from a 3-cm mass extending from the tympanic membrane to the nasopharynx. Radiography revealed a soft-tissue density in the tympanic bulla. Cytologic examination and biopsy confirmed the presence of a squamous cell carcinoma. Squamous cell carcinoma causes vestibular signs in the cat. In this cat, squamous cell carcinoma, involving the middle and inner ear, resulted in oral and vestibular signs.     

Interstitial cell tumor and Sertoli cell tumor in the testis of a cat

Testicular tumors are rarely reported in cats. We describe a case of interstitial cell tumor and Sertoli cell tumor in a cat that developed aggressive behavior and inappropriate urination 7 years after it was obtained from a shelter as an allegedly castrated 2 year old. At physical examination, the urine odor and the presence of penile papillae implied testosterone production. Testes were not palpable, but the left testis was found in the scrotum by surgical exploration and was mostly replaced by the 2 tumors. The interstitial cell tumor, but not the Sertoli cell tumor, was immunohistochemically positive for Melan-A, consistent with steroid production. Behavior improved after excision of the testis and penile papillae began to regress, but the cat was euthanatized 3 1/2 months after castration at the owner's request. Neither tumor had metastasized. The right testis was never found and was presumed to have been removed during the reported castration procedure.     

Myasthenia gravis associated with thymic neoplasia in a cat

Objective: To describe acute myasthenia gravis (MG) in the postoperative period following removal of a thymoma in an adult cat. Case summary: A 6‐year‐old spayed female domestic short haired cat weighing 6.4 kg was referred for workup and treatment of a cranial mediastinal mass. Thoracoscopic biopsies confirmed the diagnosis of thymoma. Median sternotomy was performed and approximately 95% of the mass was surgically excised. Postoperatively the cat became remarkably weak and hypercapneic. A presumptive diagnosis of MG was made following a positive response to edrophonium injection (Tensilon test). An elevated serum acetylcholine receptor antibody level was consistent with a diagnosis of MG. Initial treatment consisted of neostigmine, followed by corticosteroids and pyridostigmine. The cat responded well to therapy. New or unique information provided: This report describes a rare syndrome of postoperative weakness due to development of MG following incomplete removal of a thymoma. Post‐thymectomy weakness associated with MG has been reported in dogs and is not well described in cats.     

Feline papillomavirus infection in a cat with Bowen-like disease and cutaneous squamous cell carcinoma

A cutaneous mass in the neck was excised in a 13-year-old cat. Histopathological examination of the resected tissue revealed a multicentric squamous cell carcinoma in situ resembling Bowen's disease of man. The tumor showed a multifocal transformation to an infiltrative squamous cell carcinoma. Histological and immunohistological findings excluded actinic keratosis and feline viral plaques and allowed a classification as an irregular non-hyperkeratotic type of multicentric squamous cell carcinoma in situ. As a possible causative agent feline papillomavirus type 2 was detected using nested PCR in formalin-fixed material.     

Rectal prolapse associated with urinary bladder neoplasia in a cat

A case of feline rectal prolapse which appeared to be secondary to transitional cell carcinoma of the urinary bladder is described. The cat was reported to be incontinent and treatment was declined by the owners. Euthanasia was performed and necropsy revealed an extensive nodular thickening of the entire urinary bladder wall. A diagnosis of urinary bladder transitional cell carcinoma was made on histopathological examination.     

Use of a retained urethral catheter in three dogs with prostatic neoplasia.

Percutaneous nephrostomy catheters modified by cutting off the tubing connectors were implanted in three dogs with prostatic neoplasia to relieve or prevent stranguria. One catheter was implanted with a guide wire through a perineal urethrotomy, and two catheters were implanted via celiotomy and cystotomy. Morbidity and complications were minimal. Inflammation of the abdominal incision was present from day 4 to day 8 in the dogs with celiotomy. Urinary incontinence was continuous in one dog and intermittent in two dogs. Hematuria occurred in two dogs. The retained urethral catheter was a suitable palliative treatment for urethral obstruction in three dogs with prostatic neoplasia.     

Multifocal pleural cystic squamous metaplasia in a horse with chronic obstructive bronchopneumonia

A 10-year-old Knabstrupper stallion was euthanatized because of severe dyspnea and exercise intolerance. Postmortem examination revealed diffuse severe alveolar emphysema and chronic fibrosing pleuritis of the caudal lung. Parts of both caudal lung lobes were covered with multiple raised firm gray to yellow plaques. Histologically, these areas consisted of circumscribed pleural fibroses and cysts of metaplastic keratinizing squamous epithelium. Immunohistochemistry revealed intense labeling for cytokeratins 5/6 and 10. In addition, caudal lung lobes were severely affected by a chronic partially obliterative bronchiolitis and peribronchiolitis with multifocal pleural involvement.     

Detection of biclonal gammopathy by capillary zone electrophoresis in a cat and a dog with plasma cell neoplasia

Gammopathies associated with plasma cell neoplasms in a 15-year-old female spayed domestic shorthaired cat and a 9-year-old female spayed Rottweiler dog were evaluated by serum protein electrophoresis. In the cat, the plasma cell neoplasm was found in the liver and spleen, and an evaluable sample of bone marrow was not obtained. Some of the plasma cells had the morphologic appearance of flame cells. The paraprotein was confirmed as IgG based on agar gel immunodiffusion precipitation and both immunocytochemical and immunohistochemical staining. The dog had multiple myeloma with production of IgG and IgA paraproteins. In both cases, serum proteins were evaluated by 2 methods of protein electrophoresis: cellulose acetate electrophoresis (CAE) and capillary zone electrophoresis (CZE). In the cat and the dog, CAE showed a single large oligoclonal-like peak, which occurred in the γ-region in the cat and the β-γ-region in the dog, whereas CZE showed a biclonal gammopathy with 2 very close narrow spikes in the γ- and β-γ-regions in the cat and dog, respectively. In selected cases, CZE may be more effective than routine CAE in distinguishing oligoclonal from monoclonal or biclonal paraproteinemia.     

Multiple endocrine neoplasia type I in a cat

A 13-year-old 4.6-kg (10.2-lb) neutered male domestic long hair cat was evaluated because of a history of lethargy, exercise intolerance, and ventroflexion of the cervical portion of the vertebral column. After extensive assessment at the Veterinary Teaching Hospital at Michigan State University, the clinical signs were attributed to an aldosterone-secreting tumor of the adrenal gland. Subsequently, an insulin-secreting tumor of the pancreas as well as a functional parathyroid gland adenoma were diagnosed. All 3 masses were surgically removed, and the cat made a full recovery with complete resolution of clinical signs. The syndrome of multiple endocrine neoplasia is well described in humans, and the heritability of the condition has been confirmed. In cats and other species with 1 or more endocrine neoplasms, it is important to perform thorough clinical assessments of patients to identify other endocrine organs that may also be affected concurrently with neoplastic disease.     

Renal cell carcinoma with bone metaplasia in a horse

A case of renal tubular carcinoma with bone metaplasia is reported in a 20-year-old male, mixed breed horse having a history of weight loss and hematuria. This report includes the clinical signs, macroscopic and microscopic lesions, and the immunohistochemical findings of this neoplasm.     

Melanocytic neoplasia in the cat

Clinical features and histopathological details from 13 cases of melanocytic neoplasia in the cat are presented. The series includes cases of intraocular melanoma (n=5), limbal melanoma (n=2), dermal melanoma (n=5) and one case of metastatic melanoma for which a primary site was not identified. In the case of the intraocular tumours, there was apparent correlation between the degree of cellular pleomorphism, the mitotic rate and the extent of local infiltration. Such an association was not identified for the melanomas arising from the limbus or skin.