Development of pericardial mesothelioma in golden retrievers with a long-term history of idiopathic haemorrhagic pericardial effusion

Outcome of dogs treated with chemotherapy for mesothelioma: A retrospective clinical study on 40 cases and a literature review

Mesothelioma is an uncommon cancer in dogs for which there is no established standard of care. Chemotherapy is often suggested despite no definitive proof of efficacy. The aim of this study was to evaluate the impact of chemotherapy on survival of dogs with mesothelioma. A retrospective multicentric study was carried out. To be included, dogs needed to present an evocative clinical evolution and a morphological diagnosis of mesothelioma. Exclusion of other cause of effusion and complete clinical follow-up were also required. Fourty dogs were included, 27 received chemotherapy (group 1) and 13 did not (group 2). Groups were heterogeneous regarding the proportion of animals undergoing surgery as part of their treatment (16 in group 1, 2 in group 2; p = .016) and homogeneous otherwise. Univariate analysis showed that dogs from group 1 survived significantly longer than dogs from group 2 (MST: 366 vs. 74 days; p < .001). Complete resolution of effusion after the first chemotherapy administration positively correlated with survival in group 1 (MST: 415 vs. 160 days; p < .01). All other variable tested had no significant impact on survival in univariate analysis, but dogs undergoing surgery and dogs having serous membranes' modification at medical imaging tended to survive longer. Multivariate analysis confirmed that chemotherapy was the sole variable independently associated with survival in our study (odds ratio 5.57-6.12; p < .01).

Mediastinal Serous Cavity Mesothelioma in Two Dogs

The mediastinal serous cavity (MSC)-well documented but seldom recognized in the caudal mediastinum-is embryologically derived from the omental bursa. Mesothelioma arising from the MSC in two dogs is described. Both dogs presented with acute life-threatening hemorrhagic pleural effusion. Contrast computed tomography revealed a large solitary spherical-to-cylindrical tumor in the caudal mediastinum with variably thick, contrast-enhancing walls with lobular to frond-like proliferations that arose circumferentially and projected internally into a single, variably sized, fluid-attenuating lumen. The wall and lumen corresponded to the serous membrane and serous cavity of the MSC. Surgical exploration confirmed that both tumors arose from the mediastinum. Both had similar histologic findings, and special stains were necessary for definitive diagnosis. The tumor was nonresectable in one dog, and it was euthanized intraoperatively. The other survived 7 mo. An MSC mesothelioma should be considered a possible cause of hemothorax in dogs that may be detected on thoracic radiography and computed tomography. Differential diagnoses include esophageal foreign body or neoplasm, paraesophageal diaphragmatic hernia, MCS empyema, and pulmonary adenocarcinoma, with thoracic computed tomography helping to rule out foreign body and diaphragmatic hernia. For confirmed neoplasms, histochemistry and immunohistochemistry should be performed to differentiate between mesothelioma and pulmonary adenocarcinoma.

Clinical presentation, treatment and outcome of canine malignant mesothelioma: A retrospective study of 34 cases

Canine malignant mesothelioma (CMM) is a rare and aggressive tumour associated with a poor prognosis. Limited information is available regarding effective treatment options and prognostic factors. The purpose of this retrospective case series was to describe the clinical presentation, treatment and survival in a cohort of dogs with this disease and to investigate possible prognostic factors. Thirty-four dogs were included. Tachypnoea and dyspnoea due to pleural effusion were the most common presenting clinical signs. Twenty-two dogs had a subcutaneous access port placed and 25 dogs were treated with intracavitary and/or intravenous chemotherapy. The main protocols used were single-agent 5-FU (n = 14) and carboplatin single-agent or alternated with mitoxantrone (n = 10). The overall response rate (defined as more than 25% reduction in effusion volume) to chemotherapy treatment was 37% after 3-weeks and 24% after 15-weeks. The median survival time (MST) for all dogs was 195 days (95% CI 53-324). MST was 234 days for dogs receiving chemotherapy and 29 days for dogs not receiving chemotherapy. The 1-year survival rate was 22% for all dogs. Treatment with chemotherapy was the only significant prognostic factor associated with survival (p = .001). Further studies are needed to determine the optimal treatment approach for malignant mesothelioma in dogs. Nevertheless, effusion recurrence should be expected and the prognosis for these patients in the long-term is poor.

Pathological Findings of Canine Idiopathic Pericarditis and Pericardial Mesotheliomas: Correlation with Clinical and Survival Data

Idiopathic pericarditis (IP) and pericardial mesothelioma (PM) are causes of pericardial effusion in dogs. Pericardiectomy can be a definitive treatment in the case of idiopathic pericardial effusion or a short-term intervention for mesothelioma. The aim of the present study was to investigate which histopathologic parameters are correlated with clinical outcomes in a cohort of dogs that underwent pericardiectomy. The histopathological findings of 22 IPs and 5 PMs were compared with clinical and survival data and the immunohistochemical characterization of immune cells (CD3, CD79α, Iba1). In IP, the mesothelium was lost in 20 cases, reactive in 9, atypical in 3, and mesothelial papillary hyperplasia (MPH) was observed in 4 cases. Numerous macrophages were found in both IPs and PMs especially at the superficial layer of the pericardium. T lymphocytes were observed in mild to moderate numbers and were more numerous than B lymphocytes in both IPs and PMs. MPH was correlated with the quantity of lymphoplasmacytic infiltrate in the superficial layer, inversely related to the thickness of the pericardium, and associated with a longer overall survival. Pericardial fibrosis was present in 19 out of 22 IPs and in all mesotheliomas and was correlated with increased time from initial presentation and pericardiectomy and lymphoplasmacytic infiltrate in the deep zone. Pericardial thickness was correlated with the amount of lymphoplasmacytic and macrophagic infiltrate in the deep zone. Mesothelioma was associated with an increased number of pericardiocentesis procedures before pericardiectomy and with the presence of macrophages in the superficial pericardial layer, edema, fibrin, and hemorrhage. Disease-free interval and overall survival were significantly shorter in patients with mesothelioma compared with IP.

Outcomes of dogs with recurrent idiopathic pericardial effusion treated with a 3-port right-sided thoracoscopic subtotal pericardiectomy

OBJECTIVE

To describe a 3-port right-sided thoracoscopic subtotal pericardiectomy (TSP) to treat dogs with recurrent idiopathic pericardial effusion (RIPE) and report their long-term survival.

STUDY DESIGN

Retrospective case series.

ANIMALS

Sixteen client-owned dogs.

METHODS

Medical records were searched for dogs with idiopathic pericardial effusion that recurred after 1 or more pericardiocenteses and treated with a 3-port right-sided technique (1 subxiphoid camera port and 2 instrument ports on the right side of the dog). Follow-up consisted of direct examination or communication with referring veterinarians or owners.

RESULTS

Thoracoscopic subtotal pericardiectomy was successfully completed in all dogs, with no surgical complications. The median duration of postoperative follow-up was 191.5 days (range, 5-1345). The median survival time (MST) after surgery was 365 days (range, 5-1345); MST of dogs with a histopathological diagnosis of neoplasia (n = 4) was 76 days, whereas dogs with no evidence of neoplasia had an MST of 367 days (n = 12, P = .14). Recurrent pleural effusion was the ultimate cause of death or reason for euthanasia in 8 of 16 dogs.

CONCLUSION

The technique described here resulted in similar surgical times and outcomes for dogs undergoing TSP for RIPE compared with previous studies. Neoplasia was identified in 4 of 16 dogs.

CLINICAL SIGNIFICANCE

Thoracoscopic subtotal pericardiectomy can be readily performed with only 2 instrument ports, both on the same side of the dog, and without 1-lung ventilation. Recurrent pleural effusion led to the death of half of the dogs in this series.

Thoracoscopic pericardiectomy associated with fully implantable catheter via thoracoscopy in the management of mesothelioma in a bitch

Mesothelioma is a very aggressive malignant tumor with low survival rates that is often diagnosed belatedly. Pericardial effusion is a common consequence in cases of mesothelioma, with pericardiocentesis and pericardiectomy indicated; therefor thoracocentesis is necessary to drain the contents no longer retained in the pericardium. The present report describes a mesothelioma–carrying dog with a history of cardiac tamponade that underwent thoracoscopic pericardiectomy and, later, thoracoscopic implantation of a fully implantable catheter to function as a thoracic drain. In the consulted literature, there is no use of a fully implantable catheter for this purpose. The authors consider that there was an improvement in the quality of life.

Pericardial Hemangiosarcoma in a 10-Year-Old Papillon

A 10 yr old papillon was evaluated for lethargy, inappetence, tachypnea, and labored breathing. Physical examination findings included dehydration, tachypnea, tachycardia, and muffled heart sounds. Thoracic radiographs revealed an enlarged cardiac silhouette. Echocardiography revealed a mild volume of pericardial effusion and no evidence of right atrial tamponade or a cardiac-associated mass. Cytological analysis of the pericardial effusion was consistent with blood. There was no evidence of neoplasia. Coagulation parameters were within normal limits. Initial treatment consisted of pericardiocentesis. A subtotal pericardiectomy was later performed. No surgical complications were noted, and the dog was discharged 2 days following surgery. Results of the histological examination of the pericardium revealed hemangiosarcoma. Treatment with doxorubicin was initiated 12 days after surgery, at which time, pulmonary metastasis was suspected. The dog survived for 18 days after subtotal pericardiectomy, when it was euthanized because of complications presumably related to pulmonary metastatic disease. This is the first published report of primary pericardial hemangiosarcoma. The dog had a short survival time; thus, the response to subtotal pericardiectomy combined with adjuvant doxorubicin treatment could not be determined. Pulmonary metastatic disease was suspected 12 days following surgery. Based on this case report, pericardial hemangiosarcoma carries a guarded prognosis.

Pericardioscopic imaging findings in cadaveric dogs: comparison of an apical pericardial window and sub-phrenic pericardectomy

OBJECTIVE

To compare the pericardioscopic cardiovascular anatomy visible between apical pericardial window (PW) and sub-phrenic pericardectomy (SPP).

STUDY DESIGN

Experimental study.

ANIMALS

Canine cadavers (n = 5).

METHODS

Thoracoscopy was performed using a transdiaphragmatic subxyphoid and right and left intercostal portals. A 4 cm × 4 cm apical PW was created with endoscopic scissors. The intra-pericardiac structures were then pericardioscopically assessed using a subjective ordinal scale (0: not visible, 1: <50% seen, 2: >50% seen) before SPP. Assessment was repeated after SPP.

RESULTS

An apical PW provided limited access to the cardiac structures, with only the right ventricle >50% visible in all cadavers. The right atrium, right auricle, left ventricle, right coronary artery, and interventricular paraconal branch of the left coronary artery were observed but were typically <50% visible after apical PW. The left atrium and auricle, and heart base could not be consistently seen through an apical PW. Sub-phrenic pericardectomy significantly improved observation of all intrapericardiac structures assessed, except for the right atrium and right ventricle.

CONCLUSIONS

PW centered over the cardiac apex limits evaluation of the pericardial space during pericardioscopy compared to SPP in cadaveric dogs.

Cardiac MRI Findings in a Dog with a Diffuse Pericardial Mesothelioma and Pericardial Effusion

Veterinary cardiac MRI (cMRI) is a relatively new technique. A dog with recurrent pericardial effusion and a questionable right atrial mass lesion on echocardiography underwent cMRI. cMRI provided excellent anatomic information about the heart and surrounding structures and helped to rule out the presence of a focal mass. A diffuse thickening and enhancement of the pericardium was detected. Pericardiectomy was performed and histopathology revealed a diffuse pericardial mesothelioma. This case illustrates the potential of cMRI in the management of patients with pericardial effusion when echocardiographic findings are equivocal and illustrates cMRI findings in a case of diffuse pericardial mesothelioma.

Thoracoscopic pericardial window for management of pericardial effusion in 15 dogs

OBJECTIVES

To report short-term complications and long-term outcomes of thoracoscopic pericardial window for management of pericardial effusion in dogs.

METHODS

Retrospective study of dogs in which thoracoscopic pericardial window was performed using a three-cannula technique. Surgery time, complications, postoperative management, area of resected pericardium, histopathology results and outcome were evaluated.

RESULTS

Diagnoses included dogs with idiopathic pericardial effusion (n = 10), cardiac mass (n = 4) and mesothelioma (n = 1). One case required conversion to sternotomy. Median thoracoscopic surgery time was 52 · 5 (range, 45-80) minutes. Complications occurred in four (26%) cases. Median time to discharge was one (range, 1-6) day. Of dogs with idiopathic pericardial effusion, one is alive at 150 days, one was lost to follow-up at 180 days while eight were euthanased of which five were for unrelated reasons. All dogs with neoplastic causes died or were euthanased because of their illness. Median survival time for dogs with idiopathic pericardial effusion (635 days; range, 70-1165) was significantly longer than that for dogs with neoplasia (30 days; range, 1-107).

CLINICAL SIGNIFICANCE

Thoracoscopic pericardial window is of low morbidity with short surgery and hospitalisation times. It provides good long-term control of idiopathic pericardial effusion but short-term palliation of clinical signs in dogs with neoplastic disease.

Malignant mesothelioma: facts, myths, and hypotheses

Malignant mesothelioma (MM) is a neoplasm arising from mesothelial cells lining the pleural, peritoneal, and pericardial cavities. Over 20 million people in the US are at risk of developing MM due to asbestos exposure. MM mortality rates are estimated to increase by 5-10% per year in most industrialized countries until about 2020. The incidence of MM in men has continued to rise during the past 50 years, while the incidence in women appears largely unchanged. It is estimated that about 50-80% of pleural MM in men and 20-30% in women developed in individuals whose history indicates asbestos exposure(s) above that expected from most background settings. While rare for women, about 30% of peritoneal mesothelioma in men has been associated with exposure to asbestos. Erionite is a potent carcinogenic mineral fiber capable of causing both pleural and peritoneal MM. Since erionite is considerably less widespread than asbestos, the number of MM cases associated with erionite exposure is smaller. Asbestos induces DNA alterations mostly by inducing mesothelial cells and reactive macrophages to secrete mutagenic oxygen and nitrogen species. In addition, asbestos carcinogenesis is linked to the chronic inflammatory process caused by the deposition of a sufficient number of asbestos fibers and the consequent release of pro-inflammatory molecules, especially HMGB-1, the master switch that starts the inflammatory process, and TNF-alpha by macrophages and mesothelial cells. Genetic predisposition, radiation exposure and viral infection are co-factors that can alone or together with asbestos and erionite cause MM. J. Cell. Physiol. 227: 44-58, 2012. © 2011 Wiley Periodicals, Inc.

Pericardial mesothelioma in a Bengal tiger (Panthera tigris)

A 17-year-old Bengal tiger (Panthera tigris) presented with dyspnea and tachypnea. Radiographs revealed severe pleural and pericardial effusion, but no obvious mass. During attempts to remove the fluid under anesthesia, the cat developed cardiac tamponade and died. At necropsy, a nodular mass was found at the heart base and was identified as a pericardial mesothelioma. This is the first report of this tumor in any large cat.

Malignant mesothelioma: global incidence and relationship with asbestos

Mesothelioma incidence varies markedly from one country to another. The highest annual crude incidence rates (about 30 cases per million) are observed in Australia, Belgium, and Great Britain. A lot of data indicate a relationship between mesothelioma and asbestos. The hot areas for mesothelioma exactly correspond to the sites of industries with high asbestos use, such as shipbuilding and asbestos-cement industry. However, in many countries with high asbestos consumption, mesothelioma incidence is low. The reasons for this fact are not clear. The latency periods elapsing between first exposure to asbestos and development of mesothelioma are mostly longer than 40 yr. An inverse relationship exists between intensity of asbestos exposure and length of the latency period. Mesothelioma generally develops after long-time exposures to asbestos. Some recent studies show that the risk increases with the duration of exposure. Possible co-factors in the pathogenesis of asbestos-related mesothelioma include genetic predisposition, diets poor in fruit and vegetables, viruses, immune impairment, recurrent serosal inflammation. The study of co-morbidity in mesothelioma could give an insight into the pathogenesis of the tumor. While a levelling-off in mesothelioma incidence has been registered in some countries, a worsening of the epidemic is predictable in large parts of the world.