RADIOGRAPHIC FINDINGS IN TEN DOGS WITH THORACIC ACTINOMYCOSIS

The radiographic findings in ten dogs with thoracic actinomycosis are presented. Radiographic findins varied, but pleural effusion, pulmonary infiltrates and mediastinal masses were most commonly found. Rib involvement, commonly accompanying actinomycosis in man, was present in only one dog. The differential diagnosis of actinomycosis includes many disease entities, but based on the radiographic signs it may be possible to narrow down the number of possiblities considerably. A combination of mediastinal or pulmonary masses, pleural effusion and encapsulated fluid is strongly indicative for actinomycosis. For confirmation a bacteriological examination is indicated.     

CT features of pleural masses and nodules

Pleural space masses and nodules are rarely described on computed tomography (CT) in veterinary medicine and have only been described in patients with neoplasia. Our purpose was to describe the CT findings and diagnoses in seven patients with pleural masses and nodules. Two patients had broad-based, plaque-like pleural masses, both of which were due to neoplasia (primary pleural carcinoma, metastatic thymoma). Two patients had well-defined pleural nodules and nodular pleural thickening, one of which had mesothelial hypertrophy, and another of which had metastatic hemangiosarcoma. Three patients had ill-defined pleural nodules to nodular pleural thickening, one of which had metastatic pulmonary carcinoma, while the other two had bacterial infection with mesothelial proliferation (n = 2), fibrinous pleuritis (n = 1), and severe mediastinal pleuritis/mediastinitis (n = 2). Five of the seven patients had focal, multifocal or diffuse smooth, and/or irregular pleural thickening. Five of seven patients had pleural effusion, and postcontrast CT was useful in several patients for delineating the pleural lesions from the effusion. All patients except one had additional lesions identified on CT besides those in the pleural space. CT is useful in identifying and characterizing pleural space lesions and could be used to guide further diagnostic procedures such as thoracoscopy or exploratory thoracotomy. Both neoplastic and nonneoplastic diseases should be considered in the differential diagnoses for pleural space masses and nodules found on CT.     

Multimodality imaging characteristics of tension pyopneumothorax secondary to pulmonary carcinoma in a cat

A 3‐year‐old Himalayan cat was presented with respiratory distress. Radiography showed multiple gas opacity foci, with the locations dependent on patient positioning, and severe pleural effusion with a contralateral mediastinal shift. A large volume of fluid and air was aspirated, and the fluid components were consistent with a nonseptic exudate. A pulmonary mass, pleural nodules, and an air–fluid interface with air bubbles trapped in fibrous septations were identified using thoracic ultrasonography and CT. The cat died 2 days after imaging studies. Necropsy revealed tension pyopneumothorax caused by pulmonary carcinoma and multiple pleural metastases.     

Thoracic Radiographic Features of Silicosis in 19 Horses

Clinical records and thoracic radiographs of 19 horses with a confirmed pathologic diagnosis of silicosis were reviewed. These horses had histories of varying degrees of chronic weight loss, exercise intolerance, and respiratory distress. At the time of presentation, two horses were asymptomatic. Ten horses were geldings and nine were female. The mean age of the 19 horses was 10.7 +/- 5.5 years. Fourteen horses were identified as being from the Monterey-Carmel Peninsula of midcoastal California. An abnormal, structured interstitial pulmonary pattern was identified on thoracic radiographs in each horse. The interstitial pulmonary changes were classified as miliary (13 horses), reticulonodular (4), or linear interstitial (2), and were best visualized dorsally and caudodorsally. In addition to the abnormal interstitial pulmonary pattern, areas of pulmonary consolidation were evident caudodorsally in seven horses. Other thoracic radiographic features included: hilar lymphadenopathy (4 horses), pleural effusion/thickening (4), cranial mediastinal lymphadenopathy (2), hyperinflation (1), and a discrete pulmonary mass (1). Necropsy findings in eight horses and results of lung biopsies in an additional five horses showed a diffuse, multifocal, granulomatous pneumonia with areas of pulmonary fibrosis. Cellular infiltrates included predominantly macrophages with intracellular and/or extracellular crystalline material, occasional lymphocytes, and giant cells. Similar cellular changes were also identified, during necropsy, in the hilar and tracheobronchial lymph nodes in each of the eight horses, although gross enlargement of the lymph nodes was present in only six horses. The radiographic and pathologic findings of these 19 horses are consistent with chronic or the accelerated forms of silicosis that are recognized in humans.     

Malignant melanoma in a grey horse: case presentation and review of equine melanoma treatment options

A 15 year-old grey Thoroughbred gelding presented for investigation of chronic weight loss and recent onset of respiratory difficulty. Clinical examination confirmed tachypnoea with increased respiratory effort. Thoracic ultrasound examination detected pleural effusion. The dyspnoea was related to the large volume of pleural effusion and, following post-mortem examination, to the presence of a large mediastinal mass. Multiple pigmented masses, likely melanomas, were detected peri-anally. Thoracic radiography, cytological examination of the pleural fluid and a fine needle aspirate of a thoracic mass led to a presumptive diagnosis of malignant melanoma and this was confirmed at post mortem examination. Further metastatic spread to the central nervous system and right guttural pouch was also identified. In conclusion this case manifests the potential malignant behaviour of equine melanomas, and a review of proposed therapies for melanoma treatment highlights the therapeutic options and current areas of research.     

Pleuritis and pleural effusion in the horse: a study of 37 cases

Pleural effusion in 37 horses, including 15 acutely affected and 22 chronically affected, was found to be due to a variety of causes, including lymphocarcoma, pulmonary granulomas, coccidioidomycosis, equine infectious anemia, pulmonary abscesses, chronic pneumonia, and primary septic pleural effusion. Age, breed, or sex predilection was not found. Horses with chronic disease had weight loss, increased respiratory rate, dull respiratory sounds in the ventral portion of the thorax, and varying degrees of anorexia. Many horses were anemic. Those acutely affected had respiratory distress or signs of colic and many were anorectic. Most horses with acute primary disease had small volumes of pleural fluid. Culture and cytologic examination of pleural fluid and tracheal washings revealed the causative organism in some instances, but in a number of "primary" cases there were negative results on bacterial culture. The latter cases must be differentiated from other causes of chronic weight loss in the horse.     

Disseminated hemangiosarcoma in a horse

A 6.5-year-old horse with a history of exercise-induced pulmonary hemorrhage was admitted because of acute onset of epistaxis, dyspnea, high respiratory rate, pale mucous membranes, and dark feces. There was no clinical or laboratory evidence of a bleeding disorder, and the horse's anemia was considered to be secondary to pulmonary hemorrhage. The cause of the hemorrhage was not found on thoracic sonograms or from cytologic examination of transtracheal aspirates. Despite supportive care, the horse's health deteriorated, and it was euthanatized. Necropsy revealed blood in the thoracic and peritoneal cavities and reddish black masses in many tissues. Histologic examination confirmed a diagnosis of hemangiosarcoma. Hemangiosarcoma is a rare tumor in horses; however, as this case demonstrates, it can cause pulmonary hemorrhage and respiratory distress and may be difficult to diagnose before death.     

Diagnostic thoracoscopy

Thoracoscopy is a minimally invasive diagnostic technique that provides access to the thoracic cavity for evaluation of intrathoracic pathology without surgical intervention. Intrathoracic structures can be visualized better with thoracoscopy than with an open thoracotomy. Indications for thoracoscopy include pleural effusion, pericardial effusion, intrathoracic masses, pneumothorax, primary pulmonary disease, and trauma. Thoracoscopy is technically similar to laparoscopy, using the same basic instrumentation and principles, but is easier to perform than laparoscopy. Patient preparation, anesthesia, and patient positioning are essentially the same for thoracoscopy as for a standard open thoracotomy. Thoracoscopy provides minimally invasive access to important diagnostic information with a very low incidence of complications.     

Antemortem diagnosis of cholangiocellular carcinoma in a horse.

A 10-year-old Tennessee Walking Horse gelding was admitted to the veterinary teaching hospital for evaluation of intermittent fever, lethargy, and anorexia. Initial laboratory analyses revealed anemia and hyperfibrinogenemia. Abdominocentesis and thoracentesis yielded fluid samples with high nucleated cell counts and total protein concentrations. The tentative diagnosis was nonseptic peritonitis. The horse did not improve after 4 days of antimicrobial treatment, and pitting edema of the ventral midline developed. Thoracic radiography and ultrasonography revealed consolidation of the ventral aspect of the lung fields and pleural effusion. Pleuroscopy of the right hemithorax revealed pleural effusion and a soft-tissue mass in the caudal portion of the mediastinum. Findings on biopsy of the liver and mediastinal mass led to a presumptive diagnosis of metastatic cholangiocellular carcinoma. The horse was euthanatized, and the diagnosis was confirmed at necropsy.     

Primary cranial mediastinal hemangiosarcoma in a young dog

Primary cranial mediastinal hemangiosarcomas are uncommon tumors. A 30-kg, 2-year-old, intact female German shepherd was presented for evaluation of cachexia and respiratory distress of a few days’ duration. Lateral radiographic projection of the thorax revealed significant pleural effusion. Computed tomography revealed a cranial mediastinal mass effect adjacent to the heart. On surgical exploration, a pedunculated mass attached to the esophagus, trachea, brachiocephalic trunk, left subclavian artery and cranial vena cava without attachment to the right atrium and auricular appendage was removed and debrided by use of blunt dissection and dry gauzes, respectively. Histopathology results described the cranial mediastinal mass as hemangiosarcoma. At 8 months and 5 days post-operatively, the patient died. Primary cranial mediastinal hemangiosarcomas, although a seemingly rare cause of thoracic pathology in young dogs, should be considered in the differential diagnosis for pleural effusion and soft tissue mass effect in the cranial mediastinum. This is the first case report in a dog to describe primary cranial mediastinal hemangiosarcoma.     

Localised radiotherapy for a ferret with possible anal sac apocrine adenocarcinoma

A seven-year-old, neutered male ferret was referred to our hospital with two perianal masses (2.4x3.0 and 2.4x3.5 cm, respectively) that had recurred after initial surgical excision. Complete resection of the masses was impossible as there was deep invasion along the rectum. On histopathology, the masses were diagnosed as apocrine adenocarcinoma possibly of anal gland origin based on tumour location. There was marked response to localised radiotherapy using an orthovoltage unit at 4 Gy, twice weekly. No visible mass was detectable after six doses of radiation. However, at that time, pleural effusion was diagnosed and radiotherapy was discontinued. Cytology of a sample of the pleural effusion suggested mesothelioma, and no obvious pulmonary metastasis of anal sac adenocarcinoma were identified on thoracic radiography. The ferret died at home on day 71 after the first admission.     

Squamous cell carcinoma of the equine stomach: a report of five cases.

Five horses with squamous cell carcinoma of the stomach are described. The clinical findings included anorexia, weight loss, abdominal distension, abnormal chewing and swallowing behaviour and abdominal masses palpable per rectum in four cases. Haematological studies revealed a normocytic anaemia in three horses, and neutrophilia and hypoalbuminaemia in two. Analysis of peritoneal fluid revealed abnormal effusions in all five horses and neoplastic cells were identified in three of them. The tumours originated in the cardia and metastases were present in all the horses. Three of them had many small nodules covering the entire peritoneum.     

Atypical thymoma in a horse: Diagnostic approach and application of an alternative histological classification system

Thymoma is a rare condition in horses. This case of a 24-year-old Warmblood gelding that was presented with oedema and signs of vascular congestion of the left forelimb caused by a thoracic mass is described. The diagnostic work-up included blood chemistry, cytology of pleural effusion, ultrasonography, radiography and the visualisation and collection of a tissue sample by thoracoscopy. Finally, post-mortem findings and histopathology revealed thymic epithelial neoplasia with histomorphologic features previously unreported in horses. The unique mixture of spindle-shaped and epithelioid tumour cells in combination with clear features of malignancy suggested the application of the Moran and Suster histological classification system for thymomas in humans (Moran and Suster, 2008, Curr. Treat. Options Oncol., 9, 288), which has not been reported in an equine case before and fits well to the present case.     

Characterization of primary pulmonary adenosquamous carcinoma‐associated pleural effusion

A 10‐year‐old, female spayed Shih Tzu was presented due to weight loss, increased respiratory effort and lethargy, determined to be secondary to a congenital para‐esophageal diaphragmatic defect with partial herniation of the stomach and spleen. Four days following reduction surgery of the displaced abdominal organs thoracic effusion developed. Thoracic fluid evaluation revealed a cell‐rich, protein‐poor modified transudate with neutrophils, reactive mesothelial cells, and atypical epitheloid cells which occasionally appeared to be keratinizing, consistent with neoplastic exfoliation. Thoracic effusion recurred 2 days later, with similar characteristics as the initial sample. Computed tomography (CT) indicated consolidation and displacement of the right middle and accessory lung lobes. Exploratory thoracic surgery demonstrated a thickened, hyperemic right middle lung lobe, and thickened pericardial diaphragmatic ligament. Histologic evaluation of these tissues identified a primary pulmonary adenosquamous carcinoma with intravascular and pleural invasion. Based on these cytologic, histologic, and clinical findings, we conclude that primary pulmonary carcinomas may involve superficial thoracic structures and exfoliate into a thoracic effusion.     

THORACIC RADIOGRAPHIC FEATURES OF ANTICOAGULANT RODENTICIDE TOXICITY IN FOURTEEN DOGS

Thoracic radiographs and clinical records from 14 dogs with confirmed anticoagulant rodenticide toxicity were reviewed. Twelve of the 14 dogs were presented with a chief complaint of respiratory distress, and 12 had elevated prothrombin and activated partial thromboplastin times consistent with a coagulopathy secondary to a clotting factor deficiency. Thoracic radiographs of the 14 dogs were reviewed and abnomalities included increased mediastinal soft tissue opacity with extra and intrathoracic tracheal narrowing (4/14), increased mediastinal soft tissue opacity without tracheal narrowing (8/14), variable degrees of pleural effusion (13/14) and generalized, patchy interstitial/alveolar pulmonary infiltrates (8/14). Radiographic evidence of cardiomegaly and pulmonary artery abnormalities consistent with concurrent heartworm infestation were detected in one dog. In four dogs, dramatic tracheal narrowing was identified on the lateral thoracic radiograph caused by either mediastinal hemorrhage compressing the trachea or submucosal hemorrhage within the tracheal lumen. The trachea was displaced in a ventral direction in two dogs, and extra and intrathoracic luminal diameter narrowing was evident cranially in all four dogs. Two of these four dogs had soft tissue opacity within the dorsal trachea that extended from the larynx to the intrathoracic trachea. Twelve of the 14 dogs survived with standard treatment protocols utilizing injectable and oral vitamin K₁. One dog died from pancreatitis and disseminated intravascular coagulopathy. The other dog died soon after presentation due to severe, disseminated hemorrhage. Follow-up thoracic radiographs were made in four dogs that survived and showed resolution of the mediastinal, pleural and pulmonary changes within one to five days after the initiation of vitamin K₁ therapy.     

IMAGING CHARACTERISTICS OF INTRATHORACIC HISTIOCYTIC SARCOMA IN DOGS

In this retrospective study, two observers independently reviewed thoracic imaging studies of 39 dogs with confirmed histiocytic sarcoma. The most common findings were intrathoracic lymphadenopathy, identified by the first and second observers in 82.1% and 87.2% of dogs, respectively, and pulmonary masses (74.4% and 82.1%). Right middle lung lobe masses were significantly more common than masses in any other lung lobe (P<0.0013), with the majority having a ventral distribution. Sternal and tracheobronchial lymphadenopathy were significantly more common than cranial mediastinal lymphadenopathy (P‐values of 0.0002 and 0.012, respectively). Interobserver agreement regarding distribution of lymphadenopathy and pulmonary masses was good (κ=0.64 and 0.75, respectively). Other findings included pulmonary nodules, pleural effusion, and abnormal pulmonary patterns. In patients with CT examinations, the majority of masses were mildly to moderately enhancing and heterogeneous, poorly marginated, and bronchocentric. Lymphadenopathy and pulmonary masses are the most common intrathoracic findings in dogs with histiocytic sarcoma, and the strong predilection for the ventral aspect of the right middle lung lube may help to differentiate it from other types of neoplasia.     

Can malignant and inflammatory pleural effusions in dogs be distinguished using computed tomography?

Computed tomography (CT) is the primary imaging modality used to investigate human patients with suspected malignant or inflammatory pleural effusion, but there is a lack of information about the clinical use of this test in dogs. To identify CT signs that could be used to distinguish pleural malignant neoplasia from pleuritis, a retrospective case‐control study was done based on dogs that had pleural effusion, pre‐ and postcontrast thoracic CT images, and cytological or histopathological diagnosis of malignant or inflammatory pleural effusion. There were 20 dogs with malignant pleural effusion (13 mesothelioma, 6 carcinoma; 1 lymphoma), and 32 dogs with pleuritis (18 pyothorax; 14 chylothorax). Compared to dogs with pleuritis, dogs with malignant pleural effusions were significantly older (median 8.5 years vs. 4.9 years, P = 0.001), more frequently had CT signs of pleural thickening (65% vs.34%, P = 0.05), tended to have thickening of the parietal pleura only (45% vs. 3%, P = 0.002) and had more marked pleural thickening (median 3 mm vs. 0 mm, P = 0.03). Computed tomography signs of thoracic wall invasion were observed only in dogs with malignant pleural effusions (P = 0.05). There were no significant differences in pleural fluid volume, distribution or attenuation, degree of pleural contrast accumulation, amount of pannus, or prevalence of mediastinal adenopathy. Although there was considerable overlap in findings in dogs with malignant pleural effusion and pleuritis, marked thickening affecting the parietal pleural alone and signs of thoracic wall invasion on CT support diagnosis of pleural malignant neoplasia, and may help prioritize further diagnostic testing.     

The Association of Fibrinous Pleural Effusion with Survival and Complications in Horses with Pleuropneumonia (2002–2012): 74 Cases

Background

Fibrinous parapneumonic pleural effusions are associated with decreased efficacy of pleural fluid drainage and increased risk of medical treatment failure in people, but similar associations have not been established in horses.

Hypothesis/Objectives

We hypothesized that fibrin deposition in the pleural cavity of horses with parapneumonic effusions increases the risk of poor outcome.

Animals

Seventy four horses with bacterial pleuropneumonia diagnosed by culture and cytology of tracheal aspirates, pleural fluid, or both, and pleural effusion diagnosed by ultrasonographic examination.

Methods

Retrospective study of cases was from 2002 to 2012. Information obtained from the medical records included signalment, history, sonographic findings, treatments, and outcome. The primary outcome investigated was survival and secondary outcomes were development of complications and surgical intervention. Fisher''s exact test and logistic regression were applied for categorical variables. A t‐test was used to find differences in continuous variables between groups.

Results

Seventy four horses met study criteria and 50 (68%) survived. Fibrinous pleural effusion was associated with higher respiratory rate and pleural fluid height at admission, necrotizing pneumonia, increased number of indwelling thoracic drains required for treatment, and decreased survival.

Conclusions and clinical importance

Fibrin accumulation in parapneumonic effusions is associated with increased mortality. Direct fibrinolytic treatment might be indicated in affected horses.     

Pulmonary ultrasonographic abnormalities associated with naturally occurring equine influenza virus infection in standardbred racehorses

The purpose of this investigation was to determine if naturally occurring acute infectious upper respiratory disease (IRD) caused by equine influenza virus is associated with ultrasonographically detectable pleural and pulmonary abnormalities in horses. Standardbred racehorses were evaluated for signs of IRD, defined as acute coughing or mucopurulent nasal discharge. For every horse with IRD (n = 16), 1 or 2 horses with no signs of IRD and the same owner or trainer (n = 30) were included. Thoracic ultrasonography was performed within 5-10 days of the onset of clinical disease in horses with IRD. Horses without IRD were examined at the same time as the horses with IRD with which they were enrolled. The rank of the ultrasound scores of horses with IRD was compared to that of horses without IRD. Equine influenza virus was identified as the primary etiologic agent associated with IRD in this study. Mild lung consolidation and peripheral pulmonary irregularities were found in 11 (69%) of 16 of the horses with IRD and 11 (37%) of 30 of control horses. Lung consolidation (median score = 1) and peripheral irregularities scores (median score = 1) were greater in horses with IRD compared to horses without IRD (median score = 0; P < .05). Pleural effusion was not observed. Equine influenza virus infection can result in abnormalities of the equine lower respiratory tract. Despite the mild nature of IRD observed in this study, lung consolidation and peripheral pulmonary irregularities were more commonly observed in horses with clinical signs of IRD. Further work is needed to determine the clinical significance of these ultrasonographic abnormalities.     

Ultrasound-guided biopsy as a diagnostic aid in three horses with a cranial mediastinal lymphosarcoma

An ultrasound examination of the thorax of three horses which were performing poorly or had mild signs of colic showed that they had a cranial mediastinal mass and a pleural effusion. A cytological examination of the pleural fluid showed that it did not contain neoplastic cells. A histological examination of an ultrasound-guided core biopsy of the cranial mediastinal mass showed that in each of the three horses it was a lymphosarcoma.