Indications, outcomes and complications following lateral thoracotomy in dogs and cats

OBJECTIVES: Lateral thoracotomy is widely used for surgical management of thoracic diseases in small animals. The purpose of this paper is to describe the indications for lateral thoracotomy in dogs and cats and the associated outcomes and complications. METHODS: Medical records of animals undergoing lateral thoracotomy were reviewed and owners contacted regarding complications and survival. Relationships between signalment and treatment variables and outcome variables were investigated. RESULTS: Seventy dogs and 13 cats underwent lateral thoracotomy. Sixty-two per cent of cats and 91 per cent of dogs survived to discharge. Survival to discharge was significantly lower in cats than dogs, for neoplastic than non-neoplastic disease and in older animals. Survival to discharge was higher in animals undergoing patent ductus arteriosus ligation than in those undergoing lung lobectomy or oesophageal surgery. Survival to discharge was not related to surgeon experience. The incidence of complications was not related to species, age, disease, duration of surgery, surgeon experience or duration of thoracostomy tube placement. A low complication rate (5 per cent) was associated with thoracostomy tubes. CLINICAL SIGNIFICANCE: The approach of lateral thoracotomy has a minimal complication rate and animals with a disease requiring this approach have a high survival rate.     

Isolation of feline syncytia-forming virus from oropharyngeal swab samples and buffy coat cells

Thirteen of 40 female cats were found to be chronically infected with feline syncytia-forming virus (FeSFV). Attempts to isolate the virus from these cats by conventional methods were not successful. However, virus was isolated from oropharyngeal swab samples and buffy coat cells. A new method was used involving inoculation of actively dividing Crandell feline kidney cell cultures. Cultures were trypsinized 3 days after inoculation and, as a result, cytopathic effect was amplified and ability to detect the virus was enhanced. The FeSFV was detected in 93% (92/88) of the oropharyngeal swab samples and 100% (14/14) of the buffy coat cell specimens. Feline sera were tested by immunodiffusion for precipitating antibody against FeSFV antigen. There was 100% correlation between viral infection and the presence of precipitating antibody. Virus and antibody persisted in infected cats for the duration of this study (8 months for 5 of the infected cats). Urolithiasis was observed in 15 of 28 male cats. Although a direct relationship between FeSFV infection and urolithiasis was not established, most of these male cats (20 of 21) had antibody to FeSFV.     

Is AZT/3TC therapy effective against FIV infection or immunopathogenesis?

In vitro and in vivo prophylactic and therapeutic efficacy of AZT/3TC treatment was evaluated against feline immunodeficiency virus (FIV) infection. In vitro studies utilized FIV-infected peripheral blood mononuclear cells (PBMCs) or FIV-infected T-cell lines treated with AZT (azidothymidine) alone, 3TC alone, or AZT/3TC combination and tested for anti-FIV activity and drug toxicity. AZT/3TC combination had additive to synergistic anti-FIV activities in primary PBMC but not in chronically infected cell lines. In vivo studies consisted of four treatment groups (n=15) of SPF cats receiving AZT/3TC combination (5-75 mg/kg/drug PO BID for 8 or 11 weeks) and one control group (n=9) receiving oral placebo. Group I (n=6, 150 mg/kg/drug/day) was treated starting 3 days pre-FIV inoculation, whereas Group II (n=3, 150 mg/kg/drug/day) and Group III (n=3, 100 mg/kg/drug/day) treatments were simultaneous with FIV inoculation. Group IV treatment (n=3, 100 mg/kg/drug/day) was initiated 2 weeks post-FIV inoculation. All cats were monitored for drug toxicity and FIV infection. Eighty-three percent of cats in Group I and 33% of cats in Groups II and III were completely protected from FIV infection. A significant delay in infection and antibody seroconversion was observed in all unprotected cats from Groups I, II and III. Group IV cats had only a slight delay in FIV antibody seroconversion. Adverse drug reactions (anemia and neutropenia) were observed at high doses (100-150 mg/kg/drug/day) were reversible upon lowering the dose (20 mg/kg/drug/day). In contrast, AZT/3TC treatment had no anti-FIV activity in chronically infected cats. Furthermore, severe clinical symptoms caused by adverse drug reactions were observed in some of these cats. Overall, AZT/3TC treatment is effective for prophylaxis but not for therapeutic use in chronically FIV-infected cats.     

Diagnoses and clinical outcomes associated with surgically amputated feline digits submitted to multiple veterinary diagnostic laboratories

Amputation is commonly performed in an attempt to both treat and diagnose conditions affecting the digits of cats. The records of multiple veterinary diagnostic laboratories were searched to identify submissions of amputated digits from cats. Eighty-five separate submissions were reviewed for diagnosis, age, sex, limb of origin, and digits affected; and the original submitting clinics were surveyed to determine clinical outcome. The Kaplan-Meier product-limit method was used to determine the disease-free interval and survival time. Neoplastic disease was identified in 63 of 85 submissions, with exclusively inflammatory lesions composing the other 22 cases. In 60 (95.2%) of the neoplastic cases, a malignant tumor was identified. Squamous cell carcinoma was the most commonly identified malignant tumor (n = 15; 23.8%) and was associated with a median survival time of 73 days. Other diagnoses included fibrosarcoma (n = 14; 22.2%); adenocarcinoma, likely metastases of a primary pulmonary neoplasm (n = 13; 20.6%); osteosarcoma (n = 5; 7.9%); mast cell tumor (n = 4; 6.3%); hemangiosarcoma (n = 5; 7.9%); malignant fibrous histiocytoma (n = 2; 3.2%); giant cell tumor of bone (n = 2; 3.2%); and hemangioma (n = 2; 3.2%). Giant cell tumor of bone has not been previously described in the digits of cats. Various neoplasms can occur in the digits of cats, and submission of the amputated digit for histopathologic diagnosis is essential to determine the histogenesis and predict the clinical outcome.     

THE UTILITY OF THORACIC RADIOGRAPHIC MEASUREMENT FOR THE DETECTION OF CARDIOMEGALY IN CATS WITH PLEURAL EFFUSION

Right lateral thoracic radiographs from four groups of age and weight matched cats were evaluated retrospectively to determine the utility of thoracic mensuration in distinguishing the cause of pleural effusion. Group 1 cats had no thoracic abnormalities (n = 40); Group 2 cats had cardiomegaly without pleural effusion (n = 12); Group 3 cats had noncardiogenic pleural effusion (n = 10); Group 4 cats had cardiogenic pleural effusion (n = 18). Measurements obtained from the radiographs demonstrated tracheal elevation in cats with cardiomegaly alone and in cats with pleural effusion, regardless of cause. These data demonstrate that pleural effusion displaces the thoracic viscera dorsally, thereby mimicking cardiomegaly. Similar measurements failed to differentiate cardiogenic from noncardiogenic pleural effusion, with the exception of the lateral thoracic dimension.     

Pyothorax in 26 cats: clinical signs, laboratory results and therapy (2000-2007)

Common historical findings in 26 cats with pyothorax were dyspnea (85%), lethargy (65%), and anorexia (62%), common clinical findings were dyspnea (89%), tachypnea (73%), fever (39%), and hypothermia (27%). Frequent laboratory abnormalities were leukocytosis (68%) with a left shift (100%), anemia (65%), hypoalbuminemia (91%), hyperglobulinemia (86%), hyperbilirubinemia (60%) as well as azotemia (52%). The thoracic effusion was purulent in all cats, the thoracic fluid evaluation (n = 19) met the criteria for an inflammatory exudate (protein 32-63 g/l, median 44; cell count 54.4-390 x 10(9)/l, median 100). Cytological analysis revealed bacteria in 21 of 24 cats. From 16 cats 13 different genera were isolated, 5 cultures were without bacterial growth. In 12.5% of the cats a single population of bacteria was identified, and in 87.5% a mixture of 2-4 different bacterial species were cultured. Obligate anaerobic bacteria were the most common isolates (70%) followed by facultative anaerob (22.5%) and aerob growing (7.5%) bacteria. Bacterial culture most often yielded Fusobacteria spp., Prevotella spp., Pasteurella spp., Porphyromonas spp. and Bacteroides spp. Three cats were euthanized at the day of presentation. A thoracic lavage was performed in 22 cats; mechanical complications with the chest tubes occured in 4 cats. Thoracotomy was performed in 2 cats. Of the 23 treated cats 17 survived (74%).     

Standing Lateral Thoracotomy in Horses: Indications,Complications, and Outcomes

Objective: To describe the indications for, complications arising from, and outcome of horses that had standing lateral thoracotomy for pleural or pericardial disease. Study Design: Case series. Animals: Horses (n=16). Methods: Medical records (January 1990–December 2008) of sedated standing horses that had lateral thoracotomy were reviewed. Clinical and surgical findings, perioperative and short‐term complications were recorded. Long‐term (>6 months) outcome was determined through telephone conversations with owners and veterinarians. Results: Mean (±SD) horse age was 6.6±5.3 years (range, 1–15 years). Thoracotomy was most commonly for treatment of recurrent or chronic pleural infection (94%). Anaerobic bacteria were frequently isolated from pleural effusion associated with pleuropneumonia (63%). Right lateral intercostal thoracotomy was performed in 13 horses (82%); intercostal muscle myectomy in 5 horses; and rib resection in 1. Perioperative complications were hemipneumothorax (2 horses) and short‐term complications included cellulitis and abscessation of the thoracotomy site (6 horses). Fourteen (88%) horses survived to discharge and 46% of horses that survived returned to their previous level of athletic activity. Conclusions: Lateral thoracotomy is well tolerated by standing sedated horses with minimal perioperative and short‐term complications. Clinical Relevance: Standing lateral thoracotomy should be considered for the treatment of complicated pleuropneumonia in horses.     

Virus shedding and immune responses in cats inoculated with cell culture-adapted feline infectious peritonitis virus

Eight specific pathogen-free cats were inoculated orally or parenterally with a cell culture-adapted strain of feline infectious peritonitis virus (FIPV). Faeces and oropharyngeal swabs were monitored daily for infectious virus by inoculation of feline embryo lung cells. Virus was recovered from both sites for approximately 2 weeks after inoculation, before clinical signs of disease developed. Peripheral blood lymphocytes collected from these cats were tested in an in-vitro blastogenic assay using concanavalin A (con A) and FIPV antigen. All cats showed a profound suppression of the response to con A which only recovered to pre-inoculation levels in 2 cats, one of which survived. These 2 cats also responded to FIPV antigen on the 21st day after infection, the greater response being in the survivor. The other cats, surviving 16-18 days, developed no response to FIPV antigen. Antibody titres, measured by immunofluorescence and by virus neutralization, rose rapidly to very high levels in all cats, regardless of the route of inoculation.     

Infection and re-infection of domestic cats with various Bartonella species or types: B. henselae type I is protective against heterologous challenge with B. henselae type II

Four Bartonella species have been isolated from domestic cats, of which two serotypes/genotypes of Bartonella henselae and possibly B. clarridgeiae are human pathogens, causing cat scratch disease (CSD).Our objectives were to evaluate infection and potential cross-protection during re-infection in domestic cats with various Bartonella species or types.Thirty-six cats were primarily inoculated with B. henselae type I (n=16), B. henselae type II (n=10), B. clarridgeiae (n=6) or B. koehlerae (n=4). They were challenged with B. henselae type I (n=15), B. henselae type II (n=13) or B. clarridgeiae (n=8).All 36 cats became bacteremic (1.25x10(2)-1.44x10(6)CFU/ml) and bacteremia lasted from 37 to 582 days. Duration of bacteremia for cats inoculated with B. henselae type I was shorter than for cats inoculated with either B. henselae type II (P=0.025) or B. clarridgeiae (P=0.011).After challenge, 26 cats became bacteremic. Among the nine cats primarily inoculated with B. henselae type I and challenged with B. henselae type II, six cats stayed abacteremic. The three bacteremic cats had a transient low-level bacteremia. No bacteremia was observed in three cats primarily inoculated with B. henselae type I and challenged with another strain of B. henselae type I. Bacteremia levels in the 26 cats were significantly lower than for primary inoculation (P=0.022) and its duration was shorter (P=0.012). Among the eight cats challenged with B. clarridgeiae, duration of bacteremia in the four cats primarily inoculated with B. henselae type I was shorter than in the four cats primarily inoculated with B. henselae type II (P=0.01). Bartonella clarridgeiae inoculated cats were more likely to have relapses for both primary and secondary infections.This is the first demonstration of cross-protection, evidenced by absence of bacteremia, in cats primarily infected with B. henselae type I and challenged with B. henselae type II, whereas no cross-protection was previously shown for cats primarily infected with B. henselae type II and challenged with B. henselae type I. Such results are of major importance for future feline Bartonella vaccine development.     

Canine and feline pyothorax: a retrospective study of 50 cases in the UK and Ireland

Fifty cases (36 dogs and 14 cats) with a confirmed diagnosis of pyothorax were evaluated from five referral institutions in the UK and Ireland. Aetiology, clinical presentation, diagnosis, treatment and outcome of all cases were examined. The underlying cause of pyothorax was determined in 18 per cent of cases. Positive bacteriological cultures of the pleural fluid were obtained in 68.7 per cent of the animals. Treatment modalities included surgery and medical management, involving thoracostomy tube placement, thoracic aspiration, thoracic lavage and antimicrobial therapy. A successful outcome was achieved in 86 per cent of patients.     

Presence of Mycoplasma haemofelis,Mycoplasma haemominutum and piroplasmids in cats from southern Europe: a molecular study

Clinical symptoms produced by Mycoplasma spp. and piroplasmids in cats are sometimes similar. Diagnosis of these pathogens is difficult by microscopic procedures and molecular methods have been used as an alternative. We present in this work, the development of new molecular procedures for diagnosis of the aforementioned organisms, together with a molecular characterization of isolates found in southern European cats.A single PCR-RFLP procedure was designed for diagnosis of Mycoplasma spp. and a seminested PCR-RFLP was designed for diagnosis of piroplasmids. The 16S or 18S rRNA genes of isolates found in clinical samples were partially sequenced in all positive cases.Mycoplasma spp. was detected in 9 (30%) out of 30 symptomatic cats from Spain. Sequencing indicated that 66.6% of these isolates can be ascribed to Mycoplasma haemofelis and only 33.3% to Mycoplasma haemominutum. Partial 16S rRNA sequences obtained in Spanish isolates were very similar to those previously published from the UK and the USA.The presence of piroplasmids (Babesia and Theileria spp.) was studied in 16 cats from Spain (n=13) and Portugal (n=3). Animals analyzed were 10 cats with immunosuppressive viral infection (either FeLV or FIV), 5 asymptomatic cats and 1 cat with Babesia-compatible symptoms. Asymptomatic cats were all PCR-negative. Partial sequencing of 18S rRNA gene demonstrated that the Babesia-symptomatic cat was infected with Babesia canis canis whereas 3 (30%) out of the 10 cats with immunosuppressive viral infection were coinfected with piroplasmids (1 with B. canis canis, 1 with Theileria annae, and 1 with B. canis canis and T. annae both).     

Bacteria associated with pyothorax of dogs and cats: 98 cases (1989-1998)

OBJECTIVE: To determine the organisms most commonly isolated from pleural fluid from dogs and cats with pyothorax. DESIGN: Retrospective study. ANIMALS: 51 dogs and 47 cats. PROCEDURE: Results of bacteriologic culture of pleural fluid samples obtained by means of thoracentesis were obtained from medical records. To obtain information on in vitro antimicrobial susceptibility of organisms commonly isolated from dogs and cats, records of all dogs and cats examined during 1998 were reviewed, and information was obtained on identity and in vitro antimicrobial susceptibility of aerobic organisms isolated from samples other than urine or urinary tract samples. RESULTS: Median ages of dogs and cats were 4 years. Bacteria were isolated from pleural fluid samples from 47 of 51 (92%) dogs and 45 of 47 (96%) cats. Obligate anaerobic bacteria were isolated from 28 dogs and 40 cats. A mixture of obligate anaerobic and facultative bacteria was isolated from 17 dogs and 20 cats. Samples from cats most often yielded a member of the nonenteric group (most commonly members of the genus Pasteurella), whereas those from dogs more often yielded a member of the family Enterobacteriaceae (most commonly E coli). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that antimicrobial agents chosen for the initial treatment of dogs and cats with pyothorax should be active against a mixture of obligate anaerobic and facultative bacteria.     

Urinary tract infections in cats with hyperthyroidism, diabetes mellitus and chronic kidney disease

The prevalence of urinary tract infections (UTIs) in cats with hyperthyroidism (n=90), diabetes mellitus (DM) (n=57) and chronic kidney disease (CKD) (n=77) was evaluated retrospectively. It was found to be 12% in cats with hyperthyroidism and DM, respectively, and 22% in cats with CKD. Associations between UTIs and clinical signs, biochemical markers in serum and urinalyses were investigated. Many of the cats with UTIs had no clinical signs of lower urinary tract disease or changes in their laboratory values indicative of infection. Therefore, a urinalysis alone should not be used to exclude UTIs in these cats. UTIs are relatively common in cats with hyperthyroidism, DM and CKD, and urine cultures are recommended as part of the basic diagnostic plan for cats suspected of suffering from these conditions.     

Anaerobic bacterial infections and response to treatment in dogs and cats: 36 cases (1983-1985)

Anaerobic bacteria have been increasingly implicated as important pathogens in animals. To determine the prevalence of anaerobic bacterial infection, the results of anaerobic bacteriologic culture of 599 specimens obtained from dogs and cats hospitalized at the Colorado State University Veterinary Teaching Hospital were reviewed. Obligate anaerobic bacteria were isolated from 35% of properly submitted specimens; Bacteroides spp and Fusobacterium spp were the organisms most commonly isolated. Infections most often containing anaerobes were abscesses, pleuropulmonary infections, and abdominal infections. A complication rate of 28% was observed with anaerobic bacterial infections; failure to initially treat with an effective antibiotic increased the rate of recurrence of infection.     

Immune response of neonatal specific pathogen-free cats to experimental infection with Bartonella henselae

The purpose of this study was to determine whether neonatal cats develop and maintain a persistent bacteremia for longer than do adult cats with a normal mature immune system, and whether neonatal cats are susceptible to infection with Bartonella henselae by oral inoculation. Neonatal specific pathogen-free (SPF) cats were inoculated with B. henselae intradermally (n = 4) or orally (n = 5) or with 0.9% NaCl (n = 2). Blood was collected periodically through 16 weeks post-inoculation (PI) for serology, bacteriology and complete blood count. Cats inoculated orally or intradermally at 3-5 days of age were bacteremic through 12-16 weeks PI, similar to what is documented for adult cats inoculated intradermally or intravenously. One cat inoculated at age 2 weeks was bacteremic through 10 weeks PI; the other was not bacteremic. Intradermally inoculated neonatal cats produced serum IgG antibodies to B. henselae but orally inoculated neonatal cats did not. Infected cats with and without serum IgG antibodies to B. henselae became blood-culture negative simultaneously, suggesting that IgG is not required to clear bacteremia.     

Shedding of feline immunodeficiency virus in semen of domestic cats during acute infection

OBJECTIVE: To examine shedding of cell-free and cell-associated feline immunodeficiency virus (FIV) in semen of domestic cats during acute infection. ANIMALS: 7 specific-pathogen-free sexually intact male cats. PROCEDURE: 6 cats were inoculated IV with 5 x 10(6) 50% tissue culture infective doses of FIV-NCSU1, and 1 cat served as an uninfected (control) cat. Infection was confirmed in the 6 cats. Periodically for up to 16 weeks after inoculation, cats were anesthetized and ejaculates obtained by use of electroejaculation. Virus was isolated from filtered seminal plasma and washed seminal cells by co-cultivation with a feline CD4+ T-cell line. Seminal cell lysates were also examined for a 582-base pair segment of FIV gag provirus DNA, using a nested polymerase chain reaction amplification. RESULTS: During the acute phase of FIV infection, virus was evident in semen of 5 inoculated cats. Five cats had virus-positive seminal plasma and 3 had virus-positive cellular constituents during the study. Virus was isolated from 8/22 (36%) seminal plasma samples and 2/17 (18%) seminal cell specimens. Provirus DNA was detected in 5/24 (21%) seminal cell lysates. Cell-free virus was isolated as early as 6 weeks after inoculation, whereas cell-associated virus was isolated as early as 12 weeks after inoculation. Provirus DNA was detected in seminal cells from one cat as early as 1 week after inoculation. CONCLUSIONS AND CLINICAL RELEVANCE: Cell-free and cell-associated FIV are shed in semen of cats early during the course of infection. Samples obtained before seroconversion may contain virus. Virus shedding in ejaculates varies between and within cats during acute infection.     

Coccidioidomycosis in 48 Cats: A Retrospective Study (1984–1993)

Coccidioidomycosis was diagnosed in 48 cats. Forty-one cases were identified within a period of 3 years. Coccidioides immitis was revealed by cytological or histopathological examinations, or culture in 70% of cats. The remaining 30% of cases were diagnosed by appropriate clinical signs, radiographic lesions, and serological test results. The average age of affected cats was 6.2 years with a median age of 5.0 years. Fifty-four percent (n = 26) were female and 46% (n = 22) were male. Domestic shorthaired and longhaired breeds comprised 89% (n = 41) of affected cats. Sixty-seven percent of cases were diagnosed during the 6-month period of December through May. Cats infected with C immitis were presented for evaluation of dermatologic (56%), respiratory (25%), musculoskeletal (19%), and neurological or ophthalmologic signs (19%). Fever, inappetence, and weight loss were present in 44% of the cats. Duration of clinical signs before diagnosis was less than 4 weeks in 85% (n = 42) of cats, with an average of 3.8 weeks and a median of 2 weeks. Agar gel immunodiffusion tests were positive in all 39 cats tested at sometime during the course of their disease. Hyperproteinemia (greater than 7.9 g/dL) was present in 52% (10/23) of cases. The majority of cats (n = 39) were negative for feline leukemia virus. Antibodies to feline immunodeficiency virus were absent in the 19 cats tested. Ketoconazole was the most common antifungal agent used to treat cats with Coccidioidomycosis. Duration of treatment ranged from less than 1 week to 43 months. Thirty-two cats are currently asymptomatic, with or without treatment. Eleven cats died or were euthanized. Five cats were lost to follow-up. Ketoconazole likely is more suppressive than curative because relapses were common after discontinuing therapy.     

Immunocytochemical evaluation of epithelial–mesenchymal transition in epithelial tumors of dogs and cats

Epithelial–mesenchymal transition (EMT) plays a crucial role in metastasis of epithelial tumors; however, it is challenging to detect EMT by cytology. In the present study, EMT was visualized by fluorescence-immunocytochemistry (FICC). Air-dried smears from epithelial tumors of dogs (n=22) and cats (n=9) were stained using mouse monoclonal anti-E-cadherin and rabbit monoclonal anti‐vimentin antibodies. Enzymatic immunohistochemistry (IHC) revealed that 51.6% (8/22 in dogs, 8/9 in cats) of the cases showed EMT. In dogs, FICC could detect EMT in 62.5% (5/8) of those cases. In cats, FICC could detect EMT in 100% (8/8) of the cases. In conclusion, the present FICC method could successfully detect EMT using conventional air-dried cytology smear slides.     

Outcome of and complications associated with tube cystostomy in dogs and cats: 76 cases (1995-2006)

OBJECTIVE: To determine indications for cystostomy tube use in dogs and cats, complications associated with their use, and outcome of dogs and cats in which cystostomy tubes had been inserted. DESIGN: Retrospective case series. ANIMALS: 37 dogs and 39 cats. PROCEDURES: Information was obtained from medical records. Long-term follow-up information was obtained by use of a client questionnaire. RESULTS: Indications for cystostomy tube placement were bladder dysfunction, urinary tract rupture, obstructive urinary tract neoplasia, urinary diversion following urogenital surgery, obstructive urolithiasis, and feline lower urinary tract disease. Median time tubes were in place was 11 days, but duration of tube use was significantly longer for animals with bladder dysfunction than for animals with urinary tract trauma, urinary diversion, or urinary tract obstruction. Thirty-seven (49%) animals had tube complications. Development of complications was not significantly associated with species, age, body weight, duration of tube use, or tube type, except that animals were significantly more likely to develop complications following long-rather than short-term use. In 42 animals, the underlying condition resolved and the tube was removed; 22 animals died or were euthanatized with the tube in place. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that cystostomy tubes may be used for animals with various conditions related to problems with urine outflow. Nearly half the animals in the study developed complications related to the cystostomy tube, suggesting that potential complications should be discussed with owners prior to tube placement. However, most complications were easily resolved.     

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.