Whitney Linnenkohl Mentors Dr John Peroni DipACVS Dr Kelsey Hart DipACVIM University of Georgia College of Veterinary Medicine History and Signalment 13 Year Old Oldenburg Gelding ID: 1033363
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1. Antemortem Diagnosis of Equine Lymphoma via ThoracoscopyWhitney LinnenkohlMentors: Dr. John Peroni, DipACVSDr. Kelsey Hart, DipACVIMUniversity of Georgia College of Veterinary Medicine
2. History and Signalment13 Year Old Oldenburg GeldingPresenting complaint: weight loss and feverWeight loss of 4 months despite increase in caloric intakeFever (104oF; Ref:99-100.5o) the night before presentationReferring DVM treatment prior to presentationCeftiofur, Phenylbutazone, and Gastrogard®Transient improvement in clinical signs with treatment
3. Physical ExaminationQuiet, alert and responsiveThin body condition (3 out of 9)Severe epaxial and gluteal muscle atrophyVital parameters were within normal limitsRectal ExaminationSplenomegalyCaudal displacement of the left kidneyNo other significant abnormalities noted on initial physical examination
4. Initial DiagnosticsComplete Blood CountAnemia: 19.7 % (Ref. Range 26.3-42%)Leukocytosis: 12,200 cells/uL (Ref. Range 5,700-11,700 cells/uL) Mature Neutrophilia: 11,224 cells/uL (Ref. Range 2,900-8,500 cells/uL)Lymphopenia: 610 cells/uL (Ref. Range 1160-5,100 cells/uL)Hyperfibrinogenemia: 700 mg/dL (Ref. Range 100-400 mg/dL)Serum ChemistryHypoproteinemia: 7.8 g/dL (Ref. Range 5.4-7.5 g/dL) Hyperglobulinemia: 4.5 g/dL
5. Initial Problem ListHistory of pyrexiaCachexiaAnemiaLeukocytosis Mature NeutrophiliaLymphopeniaHyperfibrinogenemiaHyperproteinemiaHyperglobulinemiaSplenomegalyAll indicative of a chronic inflammatory conditionDifferentials: 1. Neoplasia 2. Infection (Bacterial/Fungal)
6. Diagnostic PlanOptions to identify source of inflammation:AbdominocentesisAbdominal and Thoracic UltrasoundThoracic Radiography
7. Additional DiagnosticsAbdominocentesisIncreased nucleated cell count: 22,100 cells/uL (Reference Range <5,000cells/uL)Increased total protein concentration: 5.8 mg/dL (Reference Range <2.0 mg/dL)Diagnosis: Suppurative Peritonitis
8. Additional DiagnosticsTransabdominal UltrasoundHepatic hyperechogenicityFocal hyperechoic region of the right renal medullaLIVERRIGHT KIDNEYCOLON
9. Additional DiagnosticsTransabdominal UltrasoundIncreased colonic mural thicknessFocal hypoechoic regions in spleenNo abnormalities noted on thoracic ultrasoundSPLEENCOLON
10. Additional DiagnosticsRight CaudodorsalViewMassThoracic RadiographsMass effect associated with left diaphragm
11. Diagnostic PlanInitial diagnostics indicated abnormalities in multiple organsHighly suggestive of neoplasiaMore invasive diagnostics were required to obtain a definitive diagnosis
12. Additional DiagnosticsUltrasound-Guided Liver BiopsyMild kupffer cell hemosiderosis presumed secondary to anemia of chronic disease No neoplastic cells seenUltrasound-Guided Biopsy of Liver(Courtesy Dr. M. Barton)Biopsy NeedleLIVERCOLONDUODENUM
13. Additional DiagnosticsUltrasound-Guided Splenic Aspirate Inconclusive due to low cellularityUltrasound-Guided Splenic BiopsyMonomorphic population of T-lymphocytes (stained positively for CD3)Suggestive of neoplasia but needed larger tissue sample for confirmationUltrasound-Guided Biopsy of Spleen(Courtesy Dr. M. Barton)Biopsy NeedleNote Abnormal Echogenicity of Spleen
14. Additional DiagnosticsBiopsy of the kidney was not attempted due to the location of the abnormalities within the medulla Serum Protein ElectrophoresisIncreased Alpha-2 globulin fraction: 1.66g/dl (0.31-1.31g/dl)Decreased Alpha-1 globulin fraction: 0.55g/dl (0.6-0.73g/dl)Beta and Gamma Globulin fraction within reference rangeInterpretation: Consistent with systemic inflammation, but not diagnostic for neoplasia
15. Additional DiagnosticsBecause the less invasive diagnostics were not confirmatory of neoplasia, more invasive diagnostics were needed to definitively diagnose the diseaseDiagnostic options included:Exploratory laparotomy and biopsy of affected organsThoracoscopy and biopsy of the mass found on radiographs
16. ThoracoscopyThoracoscopic biopsy of diaphragmatic mass Why choose thoracoscopy?Inconclusive results of previous abdominal histopathology Abdominal exploratory was likely to still be unrewardingPercutaneous biopsy of suspected thoracic mass difficultMinimally invasive procedure for investigating thoracic massesThorascopic View of Normal Left Hemithorax(Courtesy Dr. J. Peroni)
17. ThoracoscopyUsed for diagnosis and treatment of thoracic disease when less invasive measures are unrewarding, such as for:Exploration of thorax in patients with suspect neoplasia/pleural effusion of unknown originPleural drain placementTransection of pleural adhesionsPulmonary biopsyWindow pericardectomy
18. ThoracoscopyPerformed in standing or anesthetized horsesPortal sites vary depending on reason for surgical procedurePortals at 10th &12th intercostal spaces allow optimal visualizationAvoid vessels and nerves caudal to ribsInduced pneumothorax can cause transient hypoxia Due to ventilation/perfusion mismatch and decreased venous returnNon-Disposable Endoscopic Trocars and Cannulas(Courtesy Dr. J. Peroni)
19. ThoracoscopyStandingChemical and physical restraintLocal anesthesia at trocar sites Allows access to the majority of the thorax, except cranioventral regionsGeneral AnesthesiaLateral or dorsal recumbencyImproved view of the ventral lung surface, ventral thoracic cavity, and lateral surface of the heartPositive pressure ventilation is indicatedBilateral pneumothorax occurs more commonly than with standing thoracoscopyPatient Restrained in Stocks for Thoracoscopy(Courtesy Dr. J. Peroni)
20. Thoracoscopic ProcedurePartial pneumothorax induced in the left hemi-thoraxEndoscopic and instrument portals placedMass was visualizedEndoscopic scissors were used to excise a portion of the massAir was aspirated from the thoracic cavity to return negative pressure to the pleural spaceCaudodorsal Thoracic Portal Placement(Courtesy Dr. J. Peroni)
21. Thoracoscopy - Left Hemi-ThoraxDiaphragmPulmonary LigamentLeft Caudal Lung LobeRight Lung Lobes covered by MediastinumMassDiaphragmNormal Caudodorsal ThoraxPatient’s Caudodorsal ThoraxCaudal Lung
22. Thoracoscopic BiopsyPlease Click Image to Watch Video
23. DiagnosisHistopathology:Intense infiltrative, neoplastic population of round cells resembling lymphocytesDiaphragmatic Tumor (Hematoxylin and Eosin Stain): Mixture of Large and Small Lymphocytes(Courtesy Dr. B. Howerth)Small Lymphocytes (small nuclei)Large Neoplastic Lymphocytes (large nuclei)
24. DiagnosisImmunohistochemistry revealed a large population of B-lymphocytes (CD79 +) and a small population of T-lymphocytes (CD3+)Immunohistochemistry: CD 79+ Neoplastic Cells (B-cells)Brown stain uptake = Neoplastic B-Cell LymphocytesImmunohistochemistry: CD3 + Small Lymphocytes (T-cells)Brown Stain Uptake= T-cell Lymphocytes
25. DiagnosisT-cell Rich, B-cell LymphomaOnce the diagnosis was confirmed, the owner elected humane euthanasia of the horse
26. Equine LymphomaMesenchymal NeoplasiaOriginates from the lymphoid systemClassified based on anatomic distribution, morphology, and cell lineageOne of the most common malignant neoplasias in the horseMost frequently affects the spleen in horsesLymphoma occurs in the young horse (<5 years) more often than other types of neoplasia
27. Equine Lymphoma Clinical Signs:Lymphadenopathy, lethargy, weight loss, edema, and pyrexiaHematologic Findings:Anemia Usually the lymphocyte count is normal or lowNeutrophilic leukocytosis, hyperglobulinemia, and hyperfibrinogenemiaLeukemia (circulating neoplastic cells) is rareCommonly multicentricAffecting lymph nodes, thoracic viscera, and abdominal organs
28. Equine LymphomaT-Cell Rich, B-Cell LymphomaMore common in equine than other species T-cells are not neoplastic cellsB-cells are neoplastic cellsAll Types of Equine Lymphoma = Poor prognosisSingle case reports of chemotherapy are described but not critically evaluatedCorticosteroid therapy may be used for short term palliative therapy
29. Further ReadingAleman M. Lymphoma in Horses. In: Large Animal Internal Medicine, 4th ed. Ed: Smith B, Elsevier, St. Louis 2009. Pp. 1176-1179Meyer J, DeLay J, Bienzle D. Clinical, Laboratory, and Histopathologic Features of Equine Lympoma. Vet Pathol. 2006; 43:914-924 Lugo J. Thoracoscopy. In: Equine Surgery, 3rd ed. Ed: Auer J and Stick J. Elsevier, St. Louis 2006. Pp. 617-618Peroni JF, Horner N, Robinson N, Stick J. Equine Thoracoscopy: Normal Anatomy and Surgical Technique. Equine Vet J. 2001; 33:2-3