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Basics ⬇

Basics

Overview

  • Primary and metastatic myocardial tumors are rare tumors in dogs and cats.
  • Incidence 0.19% in dogs and 0.03% in cats.
  • Reported primary tumors include hemangiosarcoma, ectopic thyroid carcinoma, lymphoma, rhabdomyoma, rhabdomyosarcoma, thymoma, mesothelioma, chondrosarcoma, osteosarcoma, fibrosarcoma, myxoma, myxosarcoma, lipoma, peripheral nerve sheath tumor, granular cell tumor.

Signalment

  • Dog and cat-but less common in cat.
  • In dog-any age but more common between 7 and 15 years.
  • Possible increased incidence in neutered animals.
  • Increased incidence in saluki, French bulldog, Irish water spaniel, flat-coated retriever, golden retriever, boxer, Afghan hound, English setter, Scottish terrier, Boston terrier, bulldog, German shepherd dog.

Signs

  • Sudden collapse
  • Abdominal distention
  • Exercise intolerance
  • Dyspnea
  • Anorexia
  • Vomiting
  • Diarrhea
  • Acute death

Causes & Risk Factors

Unknown

Diagnosis ⬆ ⬇

Diagnosis

Differential Diagnosis

  • Idiopathic pericardial effusion
  • Pericarditis
  • Cardiomyopathy
  • Heart failure
  • Valvular disease
  • Heart base tumors

CBC/Biochemistry/Urinalysis

Anemia in some patients

Other Laboratory Tests

Serum/plasma cardiac troponin I levels are increased in patients with cardiac hemangiosarcoma and might have utility for the detection of other myocardial neoplasms.

Imaging

  • Thoracic radiography-may reveal a globoid heart suggestive of pericardial effusion, masses in the area of the atria, or metastatic lesions in the lungs.
  • Echocardiography-helpful in finding primary masses-positive predictive value of 92%, negative predictive values 64%.

Diagnostic Procedures

  • Pericardiocentesis and fluid evaluation-helpful in diagnosis of lymphoma.
  • Cytology of pericardial effusion limited in usefulness in differentiating neoplastic from non-neoplastic effusions.
  • ECG-may be normal or display a variety of arrhythmias, may see electrical alternans and small complexes with pericardial effusion.
  • Surgical biopsy of mass-if possible.

Treatment ⬆ ⬇

Treatment

Medications ⬆ ⬇

Medications

Drug(s)

  • Management of arrhythmias-lidocaine (dogs) 2–4 mg/kg IV (to a maximum 8 mg/kg over 10-minute period), CRI-25–75 µg/kg/minute IV, mexiletine (dogs) 5–8 mg/kg PO q8–12h, sotalol 1–2 mg/kg PO q12h.
  • Chemotherapy dependent on tumor type (see Lymphoma and Hemangiosarcoma chapters).

Contraindications/Possible Interactions

Chemotherapy can cause gastrointestinal, bone marrow, cardiac, and other toxicities-seek advice if unfamiliar with cytotoxic drugs.

Follow-Up ⬆ ⬇

Follow-Up

Miscellaneous ⬆

Miscellaneous

Pregnancy/Fertility/Breeding

  • It is not recommended to breed animals with cancer.
  • Chemotherapy is teratogenic-do not give to pregnant animals.

Abbreviation

ECG = electrocardiogram

Author Rebecca G. Newman

Consulting Editor Timothy M. Fan

Suggested Reading

Kisseberth WC. Neoplasia of the heart. In: Withrow SJ, Vail DE, Page RL, eds., Small Animal Clinical Oncology, 5th ed. Philadelphia: Saunders, 2013, pp. 700–706.

Rapoport G, Coleman A. Pericardial disorders and cardiac tumors. In: Smith FWK, Tilley LP, Oyama MA, Sleeper MM, eds., Manual of Canine and Feline Cardiology, 5th ed. St. Louis, MO: Saunders Elsevier, 2015 (in press).