Radiography and ultrasonography of pneumatosis intestinalis in a cat

An adult cat was presented for acute history of vomiting and collapse. Radiographs showed the presence of air within small intestinal walls and arborizing gas patterns within the liver, compatible with pneumatosis intestinalis and presumed portal venous gas, respectively. An abdominal ultrasound the following day was suggestive of gas within the intestinal wall, however, gas within the hepatic vasculature, parenchyma, or biliary tree was not evident. Due to progressive clinical deterioration of the patient, the owners elected humane euthanasia. Necropsy revealed severe necrotizing hemorrhagic enterotyphlocolitis secondary to Clostridium difficile toxin.     

Choanal atresia in a cat

CASE HISTORY: A 5-month-old domestic shorthair kitten with a history of chronic left unilateral nasal discharge was examined.

CLINICAL FINDINGS: Endoscopy and computed tomography (CT) demonstrated a complete membranous obstruction of the left nasal choana, confirming congenital unilateral choanal atresia. In addition, congenital hydrocephalus was detected on CT. Nasopharyngoscopy was performed for confirmation and treatment of choanal atresia.

DIAGNOSIS: Unilateral membranous choanal atresia associated with congenital hydrocephalus.

CLINICAL RELEVANCE: This report describes a rare congenital condition and for the first time, CT imaging provided an accurate diagnosis and allowed planning for the successful treatment of unilateral membranous choanal atresia. In addition, concurrent congenital hydrocephalus was diagnosed.     

RADIOGRAPHIC HEART-VOLUME ESTIMATION IN NORMAL CATS

Heart volume mensuration was evaluated on conventional radiographs from eight normal cats in different body positions using computed tomography (CT). Heart volumes were calculated from orthogonal thoracic radiographs in ventral and dorsal recumbency and from radiographs exposed with a vertical X-ray beam in dorsal and lateral recumbency using the formula for an ellipsoid body. Heart volumes were also estimated with CT in ventral, dorsal, right lateral and left lateral recumbency. No differences between heart volumes from CT in ventral recumbency and those from CT in right and left lateral recumbency were seen. In dorsal recumbency, however, significantly lower heart volumes were obtained. Heart volumes from CT in ventral recumbency were similar to those from radiographs in ventral and dorsal recumbency and dorsal/left lateral recumbency. Close correlation was also demonstrated between heart volumes from radiographs in dorsal/ left lateral recumbency and body weights of the eight cats.     

Radiographic,ultrasonographic, and computed tomographic characteristics of an accessory liver lobe in a cat

A 5‐year‐old male Norwegian Forest cat presented with increased hepatic serum biochemical parameters. Abdominal radiography showed an oval cranioventral mass and ultrasound revealed a mobile mass attached to one hepatic lobe. Computed tomography (CT) confirmed that the mass was attached to the right medial liver lobe. Differential diagnoses were an accessory liver lobe, benign neoplasia, and focal nodular hyperplasia. The mass was removed and histopathology confirmed the mass to be normal liver tissue. Accessory liver lobe should be included in the differential diagnosis of a mobile cranial abdominal mass with a similar ultrasonographic or CT appearance to the liver.     

Morphological assessment of cat kidneys using computed tomography

There are numerous publications about feline renal imaging information; however, none have established reference values for kidney size using computed tomography (CT). This study aimed to determine renal size and shape as well as the morphology of renal‐related structures in clinically normal cats (Felis catus) that underwent CT. Twenty‐seven healthy cats underwent pre‐ and post‐iodinated contrast‐enhanced CT. Most cat (59%) kidneys were located at the same level. The average pre‐contrast dimensions of the left kidney included a width of 2.46 ± 0.28 cm, a length of 3.52 ± 0.44 cm and a height 2.19 ± 0.31 cm, whereas those of the right kidneys were 2.45 ± 0.27 cm, 3.54 ± 0.46 cm and 2.05 ± 0.23 cm, respectively. After contrast enhancement, kidneys were slightly enlarged though not significantly. Additionally, renal length (LK or RK) was compared with second lumbar vertebra (L2) length and abdominal aorta diameter (AO). AO was significantly larger in male cats whereas L2 length appeared longer in male cats, but was not statistically different from the female cats. The LK/L2 and RK/L2 ratios were 2.29 ± 0.23 and 2.36 ± 0.20, respectively, and the LK/AO and RK/AO were 11.72 ± 1.37 and 12.05 ± 1.47, respectively. Renal vessels were examined. The renal vein was obviously larger than the renal artery, and paired renal veins were observed periodically. This study provides CT information about the feline kidney, which may help to establish reference values and information regarding renal structure prior to surgery in practice.     

Malignant mixed tumor in the salivary gland of a cat

The presence of a malignant mixed tumor, also known as a carcinosarcoma, in the salivary gland is very rare. Such tumors, which are typically aggressive, are characterized by the presence of carcinomatous and sarcomatous components. A 9-year-old neutered female domestic short-haired cat presented with swelling in the right mandibular lesion that had rapidly enlarged over the previous 3 weeks. Physical examination revealed a large, fluctuated and painless subcutaneous swelling that was associated with a firm mass. Radiographs of the head revealed a soft-tissue density that involved faint circular calcific opacity. Contrast-enhanced computed tomography revealed that the peripheral capsulated cystic area had a contrast enhanced region without bone lysis. The cat received a total excision of the mass and postoperative radiotherapy. Histopathological analysis of the mass revealed that it was a malignant mixed tumor. Metastasis to the lung was discovered 7 weeks later, at which time treatment was stopped.     

Orbital extraskeletal osteosarcoma following enucleation in a cat: a case report

Objective We present a unique case of a feline orbital extraskeletal osteosarcoma that developed 5 years post‐enucleation. History In 2002, an ophthalmologist enucleated the left eye of a 2‐year‐old neutered male DSH and submitted it to the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). COPLOW diagnosed the left eye with feline diffuse iris melanoma. In June 2007, the cat presented to another veterinarian for moderate swelling of the enucleation site. Palpation suggested a firm mass along the lateral orbital rim and an exploratory orbitotomy revealed a cyst with a mass adhered to it and the ventrolateral orbital rim. The cyst and mass were excised by the veterinarian and submitted to COPLOW. COPLOW diagnosed the tissue as an orbital conjunctival inclusion cyst and an acquired orbital osteosarcoma. Conclusions Following the enucleation, retained conjunctival epithelium became embedded in the connective tissue of the orbit and caused a cyst to develop. The cyst wall consisted of a myofibroblastic collagen‐rich matrix and acted as a nidus of chronic irritation and tumor growth. This orbital osteosarcoma resembles feline vaccine‐associated sarcomas (VAS), feline post‐traumatic ocular sarcomas, and microchip‐associated sarcomas in terms of it histopathology and its hypothesized pathogenesis related to exposure to antigenic material such as implanted epithelium, lens protein, vaccine components, and microchips as foreign bodies.     

Bilateral orbital and nasal aspergillosis in a cat

A 12-year-old, 4 kg, castrated male Persian cat was referred with a 2-month history of sneezing and bilateral mucopurulent nasal discharge. Rhinoscopically acquired nasal biopsies at this time revealed bilateral lymphoplasmacytic rhinitis. A tapering dose of oral prednisone caused the complete remission of the clinical signs, but 2 months after discontinuation of the therapy, the rhinitis recurred and the OD became exophthalmic. Computed tomography showed a soft tissue mass in both sides of the nasal cavity, both frontal sinuses, the right orbit, and to a lesser extent the left orbit. A fine needle aspirate of the right orbit revealed pyogranulomatous inflammation and Aspergillus spp. hyphae. Repeat nasal biopsy demonstrated multi-focal necrosis and a mixed inflammatory cell process which now included macrophages and scattered septate fungal hyphae. A few days later the cat became bilaterally blind and a contrast enhancing lesion involving the optic chiasm was found on magnetic resonance imaging. Despite a poor prognosis, therapy consisted of exenteration of the right orbit and trephination of both frontal sinuses before the planned initiation of medical antifungal therapy. Unfortunately, the cat died of cardiac arrest intraoperatively. Aspergillus fumigatus was cultured from both orbits at necropsy. Orbital aspergillosis has been rarely reported in cats and its relationship with lymphoplasmacytic rhinitis is unclear. In this patient lymphoplasmacytic rhinitis or previous antibiotic/corticosteroid therapy may have allowed secondary fungal invasion of the nasal mucosa and subsequently both orbits and the brain. Alternatively, Aspergillus infection may have preceded the lymphoplasmacytic rhinitis.     

Corneal hemangiosarcoma in a cat

A 10 year-old castrated male Domestic Short-hair cat with a history of chronic bilateral keratitis was referred for assessment of a red, elevated mass involving the left cornea. The rapid growth of the mass, over a month period in combination with pronounced vascularization and invasion of the corneal surface suggested an aggressive inflammatory or neoplastic process. Following keratectomy, the lesion was diagnosed histopathologically as a hemangiosarcoma. The tumor recurred locally within 3 weeks and enucleation was performed. Histopathologic examination of the globe confirmed the diagnosis and did not reveal infiltration of the limbus and conjunctiva. No signs of local recurrence or metastatic disease have been observed 18 months following enucleation. To the authors' knowledge this is the first case of primary corneal hemangiosarcoma described in the feline species.     

Orbital cellulitis and intraocular abscess caused by migrating grass in a cat

We report an unusual case of orbital cellulitis in a cat. Drainage via the pterygopalatine fossa and medical treatment were performed. Failure of resolution and loss of ocular structure and visual function with a poor prognosis led to enucleation. During surgery, plant material and purulent exudate were present in the orbit. Histopathology showed an intraocular foreign body of grass that had migrated through the sclera causing a suprachoroidal abscess with choroidal and retinal detachment.     

A matched observational study of survival in cats with enucleation due to diffuse iris melanoma

Although a small number of cases of feline diffuse iris melanoma have been documented to metastasize, the prognosis is not known. In this matched observational study, the survival time of 34 cats with enucleation due to histologically confirmed diffuse iris melanoma was recorded. These results are compared to the survival times of 83 age-matched control cats. Affected cats had enucleation between 2 and 10 years prior to the study. One group of control cats with eye disease had enucleation for either lymphoplasmacytic uveitis (27 cases), ocular trauma (seven cases), or endophthalmitis (four cases). In these control cats, enucleations were performed between 2 and 10 years prior to this study. Forty-five additional control cats presented for vaccination between 2 and 10 years prior to the study. The extent of diffuse iris melanoma at the time of enucleation in affected cats was graded according to the extent of involvement of ocular tissues and the invasiveness of the tumor. Affected cats have a significantly decreased survival compared with control cats and cats with extensive tumors at the time of enucleation have the lowest survival rates. Cats with tumors confined to the iris survive at the same rate as controls. These results suggests that early enucleation is important to avoid premature death, presumed to be due to cancer metastasis in cats with diffuse iris melanoma.     

A case of primary choroidal malignant melanoma in a cat

This report describes the clinical presentation, diagnosis, histological lesions, and prognosis of a primary choroidal malignant melanoma in a 15‐year‐old cat. The animal was presented for unilateral blindness. On ocular examination, a raised pigmented mass protruding from the posterior pole into the vitreous body was observed by diffuse transillumination and indirect ophthalmoscopy. Ocular ultrasound and computer tomography (CT) scan confirmed localization of the tumor to the posterior segment. The diagnosis of primary choroidal melanoma was confirmed by histopathology after enucleation. To our knowledge, this is the first reported case of a feline malignant melanoma with a primary choroidal localization without iris involvement.     

Differences between µCT‐imaging and conventional CT for the diagnosis of possible diseases of the middle and inner cat ear

The aim of this study was to check the relevance of using in‐vivo micro computed tomography (µCT) for the diagnosis of possible diseases of the middle and inner ear of the cat. Therefore, on the one hand, differences of the detail detectability between the two imaging methods conventional computed tomography (cCT) and in‐vivo µCT were analyzed. Six healthy cat ears were dissected and scanned several times and the obtained images were compared with each other. On the other hand, histological slices of all ears were prepared and pictures of defined anatomical structures were taken and compared with the identical sectional plane of the µCT‐images. This way it was possible to evaluate the quality and clinical limitations of the in‐vivo µCT. The results show that an in‐vivo µCT is suitable to analyze even the smallest osseous structures, such as the semicircular ducts, the spiral osseous lamina or the ossicles whereas with the help of cCT it is not possible to identify such small osseous structures because of their blurred and less detailed representation. Delicate soft tissue structures as the membranous labyrinth including hearing and vestibular organ cannot be differentiated with as well in‐vivo µCT‐ as with cCT‐images. In‐vivo µCT represent a good possibility for more detailed diagnosis of extremely fine structures which cannot be detected with cCT. Histological slices can nonetheless not be replaced by in‐vivo µCT due to a too low spatial resolution and the limitations of the in‐vivo µCT with regard to the evaluation of soft tissue dense structures.     

Multiple cutaneous histiocytomas in a cat

A 15-year-old domestic long haired cat developed nodular cutaneous masses over the right shoulder that were removed surgically. Similar masses developed in multiple cutaneous sites over the following three years. In each case, the lesions were characterized by diffuse dermal infiltration by histiocytic cells with a low mitotic rate and evidence of epidermotropism. The neoplastic population uniformly expressed class II molecules of the Major Histocompatibility Complex, but did not express the T and B lymphoid markers CD3 and CD79. Perivascular aggregates of CD3⁺ T lymphocytes were located at the deep margins of the tumour nodules. The clinical, histopathological and immunohistochemical features of these tumours are consistent with cutaneous histiocytoma. This tumour has not been previously well-documented in the cat.     

Identification of domestic cat hepadnavirus from a cat blood sample in Japan

The hepatitis B virus (Hepadnaviridae) induces chronic hepatitis and hepatic cancer in humans. A novel domestic cat hepadnavirus (DCH) was recently identified in several countries, however, the DCH infection status of cats in Japan is unknown. Therefore, we investigated the DCH infection rate of 139 cat samples collected in Japan. We identified one positive blood sample (0.78%) from a 17-year-old female cat with chronically elevated alanine aminotransferase. Phylogenetic analysis demonstrated that the DCH strain identified in this study is genetically different from strains in other countries. Further investigations are required to elucidate the evolution of DCH and the impact of DCH infection on hepatic diseases in domestic cats.     

Computed tomographic-dacryocystography (CT-DCG) of the normal canine nasolacrimal drainage system with three-dimensional reconstruction

The aims of the study were (1) to quantify the influence of selected imaging parameters on the image quality (slice thickness, mAs, and beam orientation) defining optimal conditions for scan protocols and (2) to evaluate the benefits of the 3D reconstruction techniques for visualization of NDS structures in dogs. CT-DCG was performed bilaterally in 32 heads of dogs. CT transverse images were obtained using a combination of two slice thickness values (0.8 mm and 2 mm) and two mAs values (50 mAs and 300 mAs). Two beam projection orientations were also tested: transverse plane (perpendicular to the hard palate) and oblique to the hard palate. Three-dimensional images were obtained using Volume Rendering (VR). Transverse beam projection proved to be superior for the assessment of the inferior and superior lacrimal canaliculi and lacrimal sac. In this study, there was no statistical difference regarding mAs values (50 mAs and 300 mAs) and slice thickness values (0.8 mm and 2 mm). Three-dimensional images were helpful for the assessment of topographic relationship between nasolacrimal structures and cranial landmarks.