Myofibroblastic Sarcoma in the Limb of a Horse

A case of myofibroblastic sarcoma in the left hind limb is reported in a 4-year-old male, mixed-breed horse. This report includes the clinical signs, macroscopic and microscopic lesions, and the immunohistochemical findings related to this neoplasm.     

Histiocytic sarcoma in the tarsus of a cat

A 12-year-old Persian cat was examined for a firm swelling of the right tarsal region and enlargement of the corresponding right popliteal lymph node. Cytologic evaluation demonstrated a population of malignant cells consistent with large cell lymphoma. Necropsy revealed a multi-lobulated subcutaneous mass involving the tarsus with some extension into adjacent deep muscular tissue. Histologically, the mass was composed of round cells with eosinophilic cytoplasm and pleomorphic anisokaryotic nuclei. Evidence of articular and nodal infiltration by these cells was observed. Differential diagnoses included synovial sarcoma and histiocytic sarcoma. Neoplastic cells were negative for cytokeratin, CD79a, and CD3 and positive for CD18, vimentin, lysozyme, and alpha-1-antitrypsin, most consistent with a diagnosis of histiocytic sarcoma. This is the first report of a histiocytic sarcoma involving a joint of a cat. The final diagnosis was based on the light microscopic appearance in combination with the immunohistochemical stains.     

Pleural effusions and diseases of the pleura

There are four factors that govern fluid movement to or from the pleural space: hydrostatic pressure, colloid osmotic pressure, filtration coefficient, and lymphatic function. When any of these factors are altered, fluid accumulates within the pleural space. Congestive heart failure, pancreatitis, neoplasia, hypoalbuminemia, and pulmonary thromboembolism can evoke pleural effusions by altering normal fluid transport mechanisms. This approach to pleural effusion helps to explain fluid accumulation. Chylothorax, hemothorax, and empyema are also covered in the article.     

Ureteral sarcoma in a dog

A ureteral sarcoma was diagnosed in a nine-year-old Weimaraner dog with gross haematuria, severe unilateral hydronephrosis, and hydroureter. Treatment consisted of unilateral nephrectomy and ureterectomy. This case was compared with 14 other ureteral tumours reported in the veterinary literature. Only three previous reports concerned a malignant ureteral tumour. Urinary tract neoplasms mainly involve the bladder and the kidney, and more rarely the urethra. The purpose of this paper is to report a rare case of malignant ureteral tumour in a dog.     

Synovial sarcoma in the dog–a review

A series of eight cases of synovial sarcoma in the dog is presented together with a literature review of previously reported cases. It is an uncommon tumour occuring mainly around joints and affects more males than females. It occurs most frequently in medium to large dogs of middle age. Clinical signs may develop over a long period of time and the tumour is locally invasive with an unpredictable capacity to metatasise. Radiographically it appears as a soft tissue mass which invades bone. Histological diagnosis may be difficult because of the heterogenicity of the tumour and suitable biopsy techniques are discussed. On present evidence amputation appears to be the most effective form of treatment in the dog.     

Non-neoplastic surgical diseases of the lung and pleura

Non-neoplastic diseases of the bronchi, pulmonary parenchyma, mediastinum, and pleura that are amenable to surgical management represent a wide range of unrelated etiopathogenic conditions that usually have a focal distribution. The author discusses the presurgical clinical, radiographic, and laboratory assessment and prognoses, and addresses therapeutic recommendations.     

Spindle cell sarcoma in the kidney of a dog

A spindle cell sarcoma involving the left kidney was diagnosed in a 14-year-old male Basenji. Radiography and ultrasonography were used to define the extent and location of the mass. Metastatic disease was not detected. An 8 x 5-cm mass, involving the left kidney, was resected by performing nephroureterectomy. Signs of metastasis were not detected at 3 and 6 months after surgery. Shortly after the 6-month examination, the dog was euthanatized because of perceived signs of pain attributable to cervical disk disease. Postmortem examination was not performed. Histologic examination consisted of use of hematoxylin and eosin, Masson trichrome, and van Gieson stains, and 4 immunoperoxidase techniques. On the basis of the histologic findings, the final diagnosis was spindle cell sarcoma, with the 2 most likely possibilities being leiomyosarcoma and fibrosarcoma.     

Treatment of a poorly differentiated sarcoma in the oropharynx of a horse

A 10-year-old Thoroughbred mare was referred to Tennessee Equine Hospital for evaluation and treatment of a subepiglottic mass. Physical and laboratory examinations revealed no other abnormalities. The tumour was excised through a laryngotomy site using transendoscopic laser and sharp excision. Histological evaluation revealed a poorly differentiated sarcoma with features of a leiomyosarcoma, a rarely identified neoplasm in the oropharynx of the horse. The mare developed intermittent dorsal displacement of the soft palate (iDDSP) after surgery but was able to resume full training. There was no evidence of regrowth 8 months post-operatively.     

Synovial sarcoma in a dog.

A 6.5-year-old, female Saint Bernard had a slowly growing tumor of the right tibiotarsal joint. Radiographically, bone surrounding the tumor was not involved. Subtotal surgical resection was undertaken. The tumor was classified histologically as a synovioma. Within 6 months, the tumor recurred locally and invaded the soft tissue proximal to the tibiotarsal joint. Eighteen months after initial examination, there was widespread right tibial invasion and pulmonary metastasis. The dog was euthanatized. The final histopathologic diagnosis was synovial sarcoma.     

Pulmonary histiocytic sarcoma in a rabbit

An approximately 8‐year‐old male castrated Dutch rabbit was evaluated for a 6‐day history of respiratory signs, which began as sneezing and progressed to tachypnea with anorexia. On physical examination, tachypnea and pale mucous membranes were noted. Thoracic radiographs revealed a soft tissue pulmonary mass, fine‐needle aspirates of which confirmed a neoplasia with malignant features suspicious for a histiocytic sarcoma. The rabbit was discharged and due to a rapidly deteriorating condition, the owner declined chemotherapy with Lomustine and elected euthanasia of the rabbit. The affected lung was submitted for histopathology. Histologic sections of the lung were characterized by clusters of histiocytic cells and multinucleated giant cells with occasional invasion of blood and lymphatic vessels. The histologic diagnosis was histiocytic sarcoma. To the authors' knowledge, this is the first case report of histiocytic sarcoma in a rabbit. Based on the clinical and radiologic findings in this case, histiocytic sarcoma should be included in the list of differentials for rabbits presenting with respiratory signs and evidence of a pulmonary mass.