Chemodectoma

1. Chemodectoma “Wheezi”

2. Wheezi was admitted to the Veterinary Medical Teaching Hospital. Wheezi is an 11 year old spayed female Chihuahua who presented to oncology service to initiate radiation treatment for a heart base mass that was found in the middle of February (2012).

3. History: Beginning two months ago, the owner observed that Wheezi is more lethargic and tires more easily, coughs and hacks during the day. She was presented to the referring veterinarian about one month ago for pancreatitis. At that time thoracic radiographs were done, revealing a mass cranial to the heart. Fine needle aspirates of the heart base mass revealed a tumor of endocrine/neuroendocrine origin and it was presumed to be a chemodectoma Otherwise she has been doing well and no vomiting or diarrhea since treatment of her pancreatitis.

4. Wheezi • Wheezi lives with another Chihuahua named Rizzo and a cat. • She is up to date on vaccinations and is on heartworm and flea prevention. • She stays mostly indoors but has access to the outdoors through a doggie door. • She is free fed 1/2 cup of Hills i/d a day plus chicken and rice. • She will occasionally get 1/4mg of pepcid if she feels nauseous

5. Physical Examination: • Temp: 98.5*F, Pulse: 120bpm, Resp: 40bpm • Wheezi was quiet, alert and responsive • Her mucous membranes were pink and moist and her capillary refill time was less than 2 seconds • Her eyes, ears and nose were free of discharge. • Moderate dental disease (all arcades). • Her lungs sounded normal on auscultation and there was a V/VI left systolic murmur heard on cardiac auscultation. • Abdominal palpation revealed no abnormalities and all palpable lymph nodes were within normal limits.

6. Diagnostic Tests & Results: • Complete Blood Count • Chemistry Plane • Echocardiogram • Thoracic Radiographs • Computed Tomography

7. Complete Blood Count: Chemistry Panel: • WBC 8.1 • Red Blood Cell Count 7.21 • Hemoglobin 16.0 • Packed Cell Volume 47.3 • Plasma Protein 7.7 • Platelet Count (Automated) 393,000 • Segmented Neutrophils 63 • Absolute Neutrophil 5103 • Lymphocytes 22 • Absolute Lymphocyte 1782 • Monocytes 4 • Absolute Monocyte 324 • Eosinophil 11 • Absolute Eosinophil 891 • Glucose 85 • Lactic Acid 26.6 • Cholesterol 222 • Blood Urea Nitrogen 17 • Creatinine .98 • Magnesium 2.1 • Calcium 11.2 • Phosphorus 3.6 • Total Protein 7.2 • Albumin 3.8 • Globulin 3.4 • Alanine Aminotransferases 97 • Alkaline Phosphatase 1226 • Total Bilirubin .4 • Sodium 151 • Potassium 4.5

8. Thoracic Radiographs • A 5.3 cm x 4.0 cm soft tissue opaque mass is identified within the left cranial thorax • The mass is identified within the dorsal thorax and summates with the trachea. • The mass extends into the left cranial thoracic cavity and summates with the left cranial lung lobe • Cardiac silhouette is tall and wide with left atrial enlargement • Cardiac silhouette measures 10.8 by vertebral heart score

9. Echocardiogram • The changes are consistent with chronic valve disease • The anterior mitral valve leaflet is thickened. • Severe mitral regurgitation • Mild to moderate left atrial enlargement • left ventricular internal dimension in systole is with in normal limits suggesting preserved left ventricular systolic function • Mild tricuspid regurgitation and the right heart is normal in size • Pulmonary hypertension could not be documented but cannot be ruled out

10. Echocardiogram • Mass cranial to the heart (adjacent to the main pulmonary artery (2.5 x 4.5 cm) • Not impairing blood flow and appears to be outside the pericardial sac • A trivial amount of pericardial effusion (no tamponade). • Rhythm is sinus arrhythmia • Findings revealed chronic valvular disease

11. Computed Tomography • A 4.2 cm in length, 4.3 cm centimeter in height and 3.3 cm in width, heterogeneous soft tissue attenuating mass is identified within the cranial mediastinum • The mass is heterogeneously and strongly contrast enhances with a central hypoattenuating region seen post contrast administration. • The mass extends into the left cranial thorax with compression and displacement of the left cranial lung. • Extension of the mass into the pleural cavity and pleural effusion is not identified. • The mass is vascular with suggestion of angiogenesis; the mass is closely associated with the left subclavian artery. • There is enlargement of the left atrium with left ventricular wall thickening and possible filling defects within the left ventricle.

12. Radiation Therapy • Radiation therapy for Chemodetoma • 98% of the PTV (Planned Target Volume) will be covered • 50 Gy @ 2.50 Gy per fraction • 20 fractions • Treatment April-May

13. Instructions to Owner • Medications: clindamycin 75mg BID & carprofen 25mg BID • Exercise: Due to the heart tumor limit any strenuous exercise • Diet: Normal • Call if: Wheezi does not eat or drink, begins to cough or has any vomiting/diarrhea • Please schedule an appointment for two weeks after her last treatment for a recheck evaluation.

14. Recheck visit July 2012 • Wheezi is bright, alert, and responsive • Normal bronchovesicular sounds heard bilaterally • Thorax CT revealed 4.3 cm in length, 3.3 cm in height, and 3.0 cm in width (previously 4.2 cm x 4.3 cm x 3.3 cm) • As of today (2014) Wheezi is doing well and still very active. There is no evidence of tumor growth