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Mesothelioma 651

Mesothelioma Client Education
Sheet
VetBooks.ir Diseases and Disorders

increased bronchovesicular sounds dorsally,
BASIC INFORMATION
poor peripheral pulses, jugular distention, TREATMENT
Definition paradoxical breathing, and abdominal disten- Treatment Overview
A neoplasm of mesodermal origin can arise from tion are possible. The immediate goal of treatment is removal of
the pleural, pericardial, or peritoneal surfaces • In cats, a noncompressible cranial thorax sug- body-cavity fluid that is causing clinical signs.
and has been reported arising from the scrotum gests other diagnoses: thymoma, mediastinal
or tunica vaginalis. lymphoma Acute General Treatment
• In a standing patient, thoracic percussion may • Stabilization of the patient by relieving the
Epidemiology reveal a fluid line (zone of hyporesonance) cardiovascular or respiratory embarrassment
SPECIES, AGE, SEX ventrally. is paramount.
Dogs > cats; males are overrepresented; generally ○ Remove large-volume effusions without
older Etiology and Pathophysiology delay if clinical signs are severe (pp. 1150
Mesothelioma involves a malignant transforma- and 1164).
GENETICS, BREED PREDISPOSITION tion of mesothelial cells that line body cavities. • Oxygen therapy (p. 1146) is often indicated
German shepherd dogs (particularly male) are Cavitary effusion from mesothelioma is most before centesis or obtaining blood or urine
overrepresented. Large-breed dogs are more likely due to increased capillary permeability samples if patients are extremely dyspneic
commonly affected. (parietal foci) secondary to vasculitis. or volatile in their behavior to prevent life-
threatening cardiovascular or respiratory
RISK FACTORS DIAGNOSIS decompensation (especially cats).
• Possibly asbestos exposure, which causes
mesothelioma in chronically exposed people Diagnostic Overview Chronic Treatment
• Similar histopathologic findings (i.e., fer- The diagnosis is suspected based on chronic, • For dogs with pericardial mesothelioma,
ruginous bodies) have been noted in canine recurrent body-cavity effusions with no surgical or thoracoscopic pericardectomy
and human mesothelioma. identified infectious, inflammatory, or other can palliate clinical signs and reduce tumor
neoplastic cause. Often a diagnosis of exclusion, burden (disease cytoreduction).
ASSOCIATED DISORDERS definitive diagnosis requires a biopsy. • Periodic thoracocentesis (p. 1164) or peri-
Pleural, pericardial, and/or peritoneal effusion cardiocentesis (p. 1150) can be performed
with dyspnea, acute cardiac tamponade and Differential Diagnosis when fluid accumulation or symptoms are
right-sided heart failure, or abdominal disten- • Pleural effusion (p. 791) slow to return (weeks or more).
tion, respectively, are common. • Pericardial effusion (p. 773) • Placement of a PleuralPort may aid in
• Ascites (p. 79) treatment. Some clients may be willing to
Clinical Presentation learn proper care and use of such a device
DISEASE FORMS/SUBTYPES Initial Database for home care.
• Mesenchymal form: multiple focal nodules • Effusion should be sampled and evaluated • Administration of chemotherapy by intra-
of solid or papillary neoplastic growth; with fluid analysis and cytologic assessment cavitary infusion on a q 3 weeks schedule
historically, more common (p. 1343). can be attempted for long-term control.
• Sclerosing form: characterized by an intense • CBC, serum biochemical analysis, and Chemotherapy options include cisplatin,
fibroblastic reaction and thick fibrous adhe- urinalysis: no specific changes carboplatin, mitoxantrone, bleomycin, and
sions involving all abdominal organs but • These tests should be supplemented with 5-fluorouracil.
most markedly affecting the stomach and fungal, viral, and parasitic (tick and heart- • Potential benefits (unproven on a large scale)
prostate; uncommon in dogs worm) serologic evaluations and microbial must be weighed against the real drawbacks
(fungal and bacterial) culture as clinical of possible adverse reactions to these agents.
HISTORY, CHIEF COMPLAINT suspicion and history warrant. • At this time, only small numbers of patients
Patients most commonly are presented for • Radiographs (especially after removal of as have been evaluated, and efficacy remains
dyspnea or cough and possibly abdominal much fluid as possible) unproven.
distention. This disease should be suspected • Ultrasonographic studies (abdomen, heart, • IV chemotherapy with cisplatin, carboplatin, or
in any adult patient with a cough that does and pleural space) doxorubicin may have a role in some patients.
not respond to standard treatment for non- • Consultation with an oncologist for the
specific respiratory problems or with evidence Advanced or Confirmatory Testing most current treatment recommendations
of chronic disease and effusion in any body • Contrast-enhanced ultrasonography (CEUS) is indicated, but because of the rarity of this
cavity. Depending on the anatomic location may more precisely define lesion edges, define disease, multicenter clinical trials are required
of the malignancy and the subsequent effu- the presence of necrotic and devitalized to test and develop effective treatments.
sion, the patient may present with dyspnea, areas, and the distribution of pulmonary
cough, weight loss, acute cardiac tamponade vessels so that the diagnostic utility of Possible Complications
and right-sided heart failure, or abdominal cytology and percutaneous sampling may be Pneumothorax, cardiac puncture, hemoperi-
distention. enhanced. cardium, hemothorax, infection
• Cardiac MRI (if available) if pericardial
PHYSICAL EXAM FINDINGS effusion and echocardiographic findings Recommended Monitoring
• Dyspnea due to pleural effusion in dogs are equivocal • Hourly for critical (ICU) patients: respiratory
and cats is usually identified by shallow, • Definitive diagnosis requires tissue for rates, degree of dyspnea, blood gases
inspiratory effort. histopathologic examination. • Daily to weekly for outpatients: respiratory
• Tachypnea, open-mouth breathing, cyanosis, • A normal fibronectin level in the effusion rates, quality-of-life assessments, repeat
muffled heart and lung sounds ventrally with could help rule out mesothelioma. thoracic radiographs as warranted or required

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