A RETROSPECTIVE STUDY ON THE SONOGRAPHIC FINDINGS OF ABDOMINAL CARCINOMATOSIS IN 14 CATS

A retrospective review was performed on 14 cats with histology- or cytology-proven carcinomatosis. The mean age was 12.7 years with a median of 11 years. The diagnosis of carcinomatosis was made by histology in 11 cats and cytology in three cats. Twelve cats had cytologic examination of the peritoneal free fluid and seven cats (58.3%) had evidence of malignant cells. The primary tumor site was determined in 13 cats. The most common organ locations for the primary tumor were the liver (n = 5), pancreas (n = 3), and small intestine (n = 3). Other sites were stomach and spleen in one cat each. Epithelial cell neoplasia was the primary tumor type in 11 cats. Two cats had abdominal lymphomatosis and one cat had abdominal sarcomatosis secondary to metastatic hemangiosarcoma. Free peritoneal fluid and masses in the connecting peritoneum were found in all cats (100%). Additional findings included primary or metastatic masses in abdominal organs in 10 cats (71.4%), lymph node enlargement in five cats (35.7%), pleural effusion in three cats (21.4%), parietal peritoneal masses in two cats (14.3%), and visceral peritoneal masses in one cat (7.1%). Masses in the connecting peritoneal may be a very specific finding for carcinomatosis in cats, especially with a concurrent abdominal neoplastic mass. Parietal and visceral peritoneal masses, while uncommon in this series of cats, have not been reported for other diseases and seem to strongly support a diagnosis of carcinomatosis.     

Vaccine-associated rhabdomyosarcoma with spinal epidural invasion and pulmonary metastasis in a cat

A 7-year-old, female, domestic medium-haired cat had a recurrent deep dermal mass in the interscapular region after initial surgical removal 3 months earlier. The cat had received a killed rabies vaccine and a five-in-one vaccine in the same area about 2 months prior to the first surgery. The relapsed mass was diagnosed as vaccine-associated sarcoma. The cat was euthanized 2 months later because of hind limb paralysis. At necropsy, multiple, poorly demarcated, nodular masses were seen in the muscles around the shoulders, neck, and thoracic vertebrae. Pulmonary metastasis and spinal epidural invasion at T1-T3 with regional cord compression and malacia were observed. Microscopically, the masses consisted of interwoven bundles of spindle cells with prominent multinucleated giant cell formation. The neoplastic cells stained strongly positive for myoglobin, and moderately but variably positive for vimentin, desmin, and alpha- smooth muscle actin. Phosphotungstic acid-hematoxylin staining revealed cytoplasmic striations in scattered tumor cells. The tumor was considered a vaccine-associated rhabdomyosarcoma.     

Appendicular arterial tumor embolization in two cats with pulmonary carcinoma

A 13-year-old neutered male Persian cat and an 11-year-old neutered female Persian cat were examined because of an acute onset of lameness. In both cats, conscious proprioception and reflexes were diminished in the affected limb. In 1 cat, no blood flow was detected in the left brachial artery with a Doppler ultrasonic flow detector, whereas blood flow in the right brachial artery was easily documented. In the other cat, the right femoral pulse was not palpable. Neither cat had any echocardiographic evidence of cardiac disease. In both cats, treatment was primarily supportive. One cat died, and the other was euthanatized. At necropsy, lung lobe consolidation was seen. Microscopically, there was multifocal infiltration of the lung parenchyma with cuboidal to columnar neoplastic epithelial cells. Neoplastic epithelial cells of similar morphology were identified in nodular masses in sections of muscle, and intravascular tumor emboli were identified obliterating small and large arterioles. Immunohistochemical staining of pulmonary and muscular tissue for pan-cytokeratin antigen revealed intense cytoplasmic staining of neoplastic cells. Staining for factor VIII-related antigen confirmed that clusters of neoplastic cells represented intravascular emboli. Clinical signs in the cats were attributed to arterial occlusion by tumor emboli.     

Urethral transitional cell carcinoma in a cat

A 15-year-old, male neutered cat was referred for investigation of dysuria. A retrograde urethrography was performed which showed two space-occupying masses within the lumen of the mid-to-proximal urethra. Exploratory coeliotomy revealed two urethral masses. Segmental urethrectomy was performed to resect the mass, and the lower urinary tract was reconstructed by vesico-urethral anastomosis. Histopathology showed the mass to be a transitional cell carcinoma with incomplete surgical margins. Tumour regrowth was suspected when dysuria was found approximately 318 days after surgery. Clinical signs were palliated by radiation using weekly fractions of 6 Gy for three weeks. The cat died of unknown causes 386 days postoperatively.     

Dermal intravascular leiomyosarcoma in a cat

A 10-year-old female spayed domestic shorthaired cat presented with a subcutaneous tumor between the first and second phalanges of the left hind foot. Six months after excision, a similar tumor occurred on the medial aspect of the third phalanx of the same limb. Histologically, both tumors consisted of solid masses of spindle and round cells, many of which grew within endothelial-lined vessels. Tumor cells stained positively for smooth muscle actin and vimentin, but were negative for cytokeratin, S-100, desmin, synaptophysin, factor VIII-related antigen, and neuron-specific enolase. The diagnosis was dermal intravascular leiomyosarcoma.     

Spinal cord granuloma due to Coccidioides immitis in a cat

A6-year-old 5.5-kg female spayed domestic short-haired cat from Tucson, AZ, presented with an ˜5-day history of progressive pelvic limb weakness. The owners had returned from a weekend away to find the cat unable to use her left pelvic limb. Approximately 2 months previously, the cat had a cough and was treated for presumptive asthma with 5 mg prednisone PO q24h. The cat had a similar cough 1 year previously and seasonal allergy was suspected. The cough resolved and prednisone treatment was discontinued. Other past pertinent history included a skin problem ˜4 years previously that was described as alopecia, erythema, and pruritus of a pelvic limb. This problem had been diagnosed as an allergy and had since resolved. The cat was housed exclusively indoors and had been adopted as a kitten from a local retail store. Viral titers (FeLV and FIV) were negative, and regular vaccinations and veterinary examinations had been completed     

Intestinal T-cell lymphoma with severe hypereosinophilic syndrome in a cat

A Japanese domestic long-hair cat of about 8 years of age was presented with vomiting and hematochezia and was found to have significant hypereosinophilia. Bone marrow aspiration revealed moderate increases of eosinophilic lineages. Histopathological examination revealed mild eosinophilic and epitheliotropic T-lymphocytic infiltrations in the duodenum. Although the cat remained asymptomatic with only prednisolone administration, the cat presented with hematemesis, weight loss, and severe anorexia 512 days after the initial presentation. Subsequently, gastrointestinal perforation developed, and the cat died on Day 536. Histopathological examination of autopsy specimens revealed mixed cellular infiltration including eosinophils and neoplastic lymphocytes in the intestinal lymph nodes, intestine, liver, spleen, and pancreas. Immunohistochemical examination supports a diagnosis of intestinal T-cell lymphoma with severe hypereosinophilic syndrome.     

Aberrant migration and surgical removal of a heartworm (Dirofilaria immitis) from the femoral artery of a cat

A cat was evaluated for an acute‐onset of right pelvic limb paresis. Thoracic radiographs revealed normal cardiac size and tortuous pulmonary arteries. Abdominal ultrasound identified a heartworm (HW) extending from the caudal abdominal aorta into the right external iliac artery and right femoral artery. The cat was HW‐antigen positive. Echocardiography revealed a HW within the right branch of the main pulmonary artery and evidence of pulmonary hypertension. An agitated‐saline contrast echocardiogram revealed a small right to left intracardiac shunt at the level of the atria. Surgical removal of the HW was performed with no substantial postoperative complications. There was return of blood flow and improved motor function to the limb. The cat remains mildly paretic on the affected limb with no other clinical signs.     

Metastatic synovial cell sarcoma in two cats

Synovial cell sarcoma (SCS) with metastasis to the regional lymph node was diagnosed in two cats. Synovial cell sarcomas are rare in cats and metastatic SCS has not previously been reported. In both cases, treatment consisted of limb amputation and adjuvant doxorubicin. Local tumour recurrence and pulmonary metastases were diagnosed in one cat 316 days postoperatively. This cat died of chronic renal failure 444 days after limb amputation. The second cat died of an acute pulmonary thromboembolism 41 days postoperatively without evidence of local tumour recurrence or metastatic disease.     

Mycobacterial neuritis in a cat

A 2-year-old spayed female domestic shorthair cat was referred for evaluation of rapidly progressive lameness of the right hind limb, which was paralyzed. Histologic examination of biopsy specimens revealed pyogranulomatous inflammation affecting the sciatic, common peroneal, and tibial nerves, and slender, beaded, acid-fast bacilli within macrophages, nerve fibers, and degenerate axons. A diagnosis of mycobacterial neuritis was made and the cat was treated with clofazimine and enrofloxacin for extended periods. Treatment was partially effective; the goal of returning normal function to the limb was not achieved, but disease progression was halted and the cat remained a viable pet.     

LINEAR OSTEOCHONDROMATOSIS IN A CAT

A domestic shorthair cat was presented with quadriparesis and lumbar hyperesthesia that progressed over 4 months. There were linear and amorphous radiopaque masses throughout the soft tissue surrounding the long bones, vertebral bodies, ribs, pelvis, and scapula. The diagnosis of osteochondromatosis was confirmed by histopathology. Unlike previously reported patients with osteochondromatosis, most of the calcified masses in this cat were not connected to the periosteum; some were linear and were arranged parallel to the long bones involved.     

Metastatic carcinoma in the ulna of a cat secondary to a suspected pulmonary tumour

A 14-year-old male neutered Burmese cat presented for investigation of right fore limb lameness that was non-responsive to anti-inflammatory drugs and opioids. Thoracic radiography showed multiple pulmonary soft tissue nodules and a larger cavitated mass. Right elbow radiographs revealed marked peri-articular proliferation of new bone and periosteal reaction primarily affecting the ulna. Histopathological examination of an incisional biopsy of the right ulna revealed neoplastic proliferation of epithelial cells; this was confirmed as a poorly differentiated carcinoma with immunohistochemistry. Amputation of the right fore limb was performed at the owner's request. After surgery, radiographs of the limb showed progression of bone proliferation. Repeat pathological analysis confirmed a metastatic carcinoma. The cat deteriorated 3 days after surgery and was euthanased a week later as a result of severe respiratory distress. This case represents an unusual case of metastasis of a suspected primary lung tumour to the ulna in a Burmese cat.     

Pathological femoral fracture due to rhabdomyosarcoma in a cat

An eight-year-old neutered male domestic shorthaired cat was presented with non-weightbearing lameness of the right hindlimb. On radiography, a pathological, metaphyseal femoral fracture was apparent, with areas of bony lysis directly surrounding the fracture site. The cat underwent amputation of the limb. Histopathological examination revealed the presence of a tumour of mesenchymal cells with cytoplasm-containing vacuoles which stained positive with the periodic acid-schiff reaction, indicative of glycogen granules that may be found in rhabdomyosarcoma cells. In addition, the tumour cells stained positive for vimentin and desmin on immunohistochemical examination, thus confirming the diagnosis of rhabdomyosarcoma. In spite of the radical surgery performed, the cat was euthanased due to a recurrence at the amputation site four and a half months later.     

Pulmonary adenocarcinoma with osteoblastic bone metastases in a cat

A 12-year-old male cat with depression and dyspnoea was presented for investigation. Radiography and computed tomography revealed hydrothorax and solid masses involving the sternum, ribs and thoracic vertebrae. The cat died two days after first presentation, and postmortem examination revealed lung masses and proliferative bony lesions. Histologically, a neoplastic proliferation of epithelial cells was seen in the lungs, with a large amount of collagen and deposits of cholesterin. The bone lesions were also composed of neoplastic epithelial cells and abundant calcified osteoid, without atypia. A diagnosis of pulmonary adenocarcinoma with osteoblastic bone metastases was made. This is the first reported case of osteoblastic metastases in the cat.     

Systemic Exophiala jeanselmei infection in a cat

A 14-year-old spayed domestic shorthair cat was referred for ultrasonographic evaluation of abnormally shaped kidneys. Multifocal lesions were detected ultrasonographically in the liver and kidneys; a fine-needle aspirate of the kidneys was performed, and numerous clumps of fungal hyphae were identified. The following day, the cat was recumbent with advanced neurologic signs. The cat was euthanatized, and a necropsy was performed. Multifocal granuloma-like masses were seen on the liver, kidneys, abdominal wall, mesentery, thoracic wall, pericardium, and epicardium. Similar lesions were found on the cervical portion of the spinal cord, the cerebrum, and cerebellum. Exophiala jeanselmei, an organism of the phaeohyphomycotic group, was identified on fungal culture. To our knowledge, systemic infections caused by this organism have not been reported. However, phaeohyphomycotic infections are believed to be an emerging disease in humans.     

MAGNETIC RESONANCE IMAGING IN THE DIAGNOSIS OF LYMPHOMA INVOLVING THE BRACHIAL PLEXUS IN A CAT

An 11-year-old, neutered, female Domestic Long Hair cat had a 3-week history of left forelimb lameness. Conscious proprioception and postural reflexes were absent on the left thoracic limb. The cat had slightly reduced placing and hopping responses on the left pelvic limb, absent cutaneous trunci muscle reflex on the left side, and left triceps muscle atrophy. Magnetic resonance imaging revealed a 2 x 2 x 2 cm mass in the region of the left brachial plexus. The cat was treated by left forelimb amputation and hemilaminectomy. Histopathology of the brachial plexus revealed lymphoma.     

Fibrosarcoma with sarcomatosis and metastasis in a FeLV-negative cat

A 6-year-old, spayed female, mixed shorthair cat presented to the emergency service at The Ohio State University Veterinary Medical Center for evaluation of hypercalcemia, a right eye mass, and multiple intrathoracic and intra-abdominal masses. Cytologic evaluation of one of the abdominal masses revealed a uniform population of large, anaplastic mesenchymal cells found individually, in loose aggregates, and occasionally associated with pink, extracellular matrix. The cytology was consistent with a malignant mesenchymal neoplasm, with primary consideration given to fibrosarcoma and hemangiosarcoma. The cat was euthanized and histopathology confirmed disseminated fibrosarcoma. Fibrosarcoma comprises 12%-41% of feline cutaneous tumors and affects cats at a mean age of 9.6 years. Three manifestations of fibrosarcoma predominate in cats: spontaneous solitary fibrosarcoma, vaccine-induced/injection site fibrosarcoma, and oncogene-induced (FSV) fibrosarcoma. The history, signalment, and results from diagnostics performed did not support solitary fibrosarcoma or injection-induced sarcoma. Although some criteria fit with virally induced fibrosarcoma, such as age and the presence of multiple fibrosarcomas, the neoplastic population was negative for FeLV IHC. The presence of fibrosarcomas throughout the pleural and peritoneal cavity was most compatible with sarcomatosis and the distant metastasis of an unidentified primary neoplasm. To the authors’ knowledge, this is the first reported case of sarcomatosis in a FeLV-negative cat.     

Physeal dysplasia with slipped capital femoral epiphysis in a cat

A 14-month-old, intact male cat presented with acute onset, severe right hind limb lameness. Pelvic radiographs, excision of the femoral head, and histopathologic examination resulted in a diagnosis of physeal dysplasia with slipped capital femoral epiphysis. The cat rapidly regained use of the affected limb.     

ULTRASONOGRAPHIC EVALUATION OF BRACHIAL PLEXUS TUMORS IN FIVE DOGS

Five dogs with unilateral thoracic limb lameness, neurologic deficits, muscle atrophy, and pain, or a combination of these signs, were examined using ultrasonograghy. Large, hypoechoic tubular masses that displaced vessels and destroyed the normal architecture were found in each dog. The affected axilla of each patient was then imaged with computed tomography or magnetic resonance to fully assess the extent of the masses. We describe the use of ultrasound in screening patients for brachial plexus tumors.     

Veins of the thoracic limb of the Van cat

The drainage of the thoracic limb of the Van cat was performed by the superficial and deep vein systems. The superficial system was constituted by the cephalic vein and its branches. The deep vein system was constituted by the axillary vein and its branches. The two vein systems anastomosed with each other at various points along their courses. The cephalic vein emerged from the external jugular vein together with the superficial cervical vein. The axillary vein continued the subclavian vein. It ran caudoventrally and gave off the subscapular vein, at the level of the shoulder joint, then gave off two independent branches, which were the external thoracic veins. Then the rest of the vessel continued as the brachial vein. The thoracodorsal vein was formed by the communicate ramus vein which arose between the subscapular vein and the brachial vein. The cranial circumflex humeral vein arose double from the subscapular vein. One of them anastomosed with the deep brachial vein and the other one drained the biceps and the deep pectoral muscles. The cranial interosseous vein from the caudal aspects of the brachial vein and passed the interosseous space of the antebrachium then ran to the lateral aspect of the forearm. The caudal interosseous vein arose from the ulnar vein (in two specimens) and the median vein together with the ulnar vein (in two specimens) or independently from the median vein (in one specimen). Although many similarities were found in the veins of the thoracic limb of the Van cat as compared with the domestic cat, some significant differences were noted in the origin, course, anastomosing and ramification of veins of the thoracic limb.