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.     

Prostatic adenocarcinoma in a cat

Prostatic adenocarcinoma was diagnosed in an 11-year-old neutered cat. Clinical signs of the disease included hematuria and a mass in the caudal portion of the abdomen. Prostatectomy was performed. Doxorubicin was administered IV at a dosage of 30 mg/m2 of body surface, followed by cyclophosphamide (300 mg/m2, IV). After 4 treatments, low urine specific gravity and proteinuria developed, and treatment was discontinued. The cat was euthanatized 10 months after surgery because of recurrence of the neoplasm. Necropsy revealed metastasis to the lungs and pancreas.     

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.     

Malignant Sertoli cell tumor in the retained abdominal testis of a unilaterally cryptorchid horse

A 13-year-old Morgan gelding was evaluated because of a mass in the caudal region of the abdomen. The horse had been presumed to be a gelding, but necropsy findings revealed a retained testis in the right retroperitoneal space. Histologically, the retained testis contained neoplastic cells; metastases were identified in the liver, spleen, lungs, and sublumbar lymph nodes. Immunohistochemical examination of the testis and metastatic tissues confirmed the diagnosis of malignant Sertoli cell tumor. Testicular neoplasms are infrequently reported in stallions. Seminomas are most commonly reported, whereas Sertoli cell tumors are considered to be rare. Typical biological behavior of Sertoli cell tumors in horses is unknown. To the authors' knowledge, there have been 2 reports of Sertoli cell tumors in horses; the tumors developed in descended testes, and 1 tumor was malignant.     

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.