Susan M. Newell

Primary Mesenchymal Chondrosarcoma in the Pericardium of a Dog

hemogram was normal except for a monocytosis (2,820/ ml), a mild lymphopenia (880/ml), and an increase in fibrinogen (500 mg/dl). The chemistry profile was normal except for an increase in alkaline phosphatase (851 IU/liter). Survey thoracic radiographs revealed a greatly enlarged, globoid cardiac silhouette with a small volume of pleural effusion. Moderate hepatomegaly with smooth margination was noted in the abdominal radiographs. Differential diagnoses at this time included benign pericardial effusion, atrial hemangiosarcoma with pericardial hemorrhage, dilated cardiomyopathy and a thoracic or cardiac tumor. An ultrasound-guided fine needle aspirate of the mass was obtained. Wright‐Giemsa-stained fine needle aspirates of the pericardial mass revealed moderate numbers of neoplastic round to spindle-shaped cells that were arranged individually and in small clumps within a lightly stippled, eosinophilic background. These cells were characterized by round to oval nuclei with a high nuclear to cytoplasm ratio, coarse nuclear chromatin pattern, and prominent often multiple nucleoli. Anisokaryosis and anisocytosis was moderate to marked. The cytoplasm was deeply basophilic and some of the cells contained variably sized purple granules. Multinucleated cells were also noted, containing from 2 to more than 100 nuclei (Fig. 1). Amorphous, pink, extracellular material was noted around a few of the cellular clumps. A cytologic interpretation of malignant mesenchymal neoplasia was made. The owners declined further evaluation and the dog was euthanatized. A complete necropsy was performed. Approximately two-thirds of the thoracic cavity was occupied by a large, firm intrapericardial mass that displaced the lungs dorsad and caudad. Incision of the pericardium revealed posterior displacement of the heart by a 14

Magnetic Resonance Imaging in Psittacine Birds with Chronic Sinusitis

Abstract Ten psittacine birds (3 African grey parrots [Psittacus erithacus], 3 blue and gold macaws [Ara ararauna], 2 scarlet macaws [Ara macao], a harlequin macaw [Ara ararauna × macao], and a yellow-naped Amazon parrot [Amazona ochrocephala auropalliata]) with histories of chronic sinusitis were referred for evaluation before possible surgical therapy. The duration of clinical signs in these birds ranged from 8 months to 11 years, and response to conventional medical therapy had been poor. Diagnostic procedures performed in each bird included a physical examination, complete blood count, plasma biochemical analysis, survey whole body and skull radiographs, and skull magnetic resonance imaging. In 7 of the 10 birds, a discrete lesion was localized by using magnetic resonance imaging. Six of these 7 birds had surgery performed to remove the lesion. Four granulomas, a mucocele, and a polyp were diagnosed by histopathologic examination. The chronic sinusitis resolved after surgery in 5 birds. Magnetic resonance imaging proved to be an excellent diagnostic tool for examining the avian infraorbital sinus, allowing identification, localization, and characterization of lesions within the sinuses.

Imaging techniques for avian lower respiratory diseases

Radiography is the most frequently used imaging technique to assess avian lower respiratory disease. The unique architecture of the avian respiratory system results in variations of radiographic appearances that are markedly different from the traditional pulmonary patterns frequently seen in mammals such as alveolar, bronchial, or interstitial. Alveolar lung disease, the hallmark of pneumonia in mammalian imaging, is not identified in avian lungs because the terminal airways consist of interconnecting bronchi and parabronchi without well-developed smaller compartments. Pathological changes of avian lungs are most commonly recognized radiographically as increased soft-tissue opacity with loss of the normal reticulated pattern. Avian lungs are relatively noncompliant and firmly adhered to the thoracic wall; thus, total lung volume is relatively constant throughout respiration, and conditions such as atelectasis do not occur. This review will address the common radiographic findings associated with avian lower respiratory disease. In addition, the potential applications of computerized axial tomography (CT) and magnetic resonance imaging (MRI) in avian respiratory disease will be discussed.

Serratia marcescens Infection in a Gopher Tortoise, Gopherus polyphemus, and use of Magnetic Resonance Imaging in Diagnosing Systemic Disease

ABSTRACT A wild-caught gopher tortoise, Gopherus polyphemus, was examined on three occasions for evaluation and treatment of subcutaneous masses. Following histopathologic examination and microbiologic culture of the masses, a diagnosis of Serratia marcescens abscesses was made. Despite surgical excision of the abscesses followed by two courses of treatment with ceftazidime (20 mg/kg q 72 h for 2 wk) given two months apart, further abscess formation occurred. While radiography failed to reveal any internal masses, magnetic resonance imaging revealed masses within the lung parenchyma. The tortoise was euthanatized, necropsy revealed multiple abscesses in the liver, kidney, and lung. Magnetic resonance imaging was found to be a useful diagnostic tool in a case where abscesses within the coelom were suspected.