Case Report: Carcinoma and Lymphoma in a Warmblood Gelding

1. Case Report: Carcinoma and Lymphoma in a Warmblood Gelding Elizabeth Cunningham, LVMT DVM candidate 2020 MU CVM, Columbia, MO Mentor: Lynn M. Martin, DVM, MPH, DACVIM (LAIM)

2. Signalment and Presenting Complaint • 18 year old Warmblood gelding • Use: Stadium show jumping • February 2019 • Horse was perceived to be extremely painful when being ridden due to friction of the masses rubbing between the hind legs. • Horse had chronic excessive tearing and mucopurulent discharge from the left eye (OS), also perceived to be painful. PHOTO COURTESY: Dr. Lynn M. Martin

3. Previous History February 2015 Squamous cell carcinoma (SCC) of the nictitating membrane OS Excision by rDVM, incomplete margins March 2015 First presented to the MU CVM to initiate yttrium radiation therapy of the periorbital region of OS SCC June 2015 Routine re-evaluation at the MU CVM - No evidence of regrowth or metastasis of OS SCC

4. History • October 2018 • Returned to MU CVM for ophthalmic examination due to increased squinting and tearing OS; SQ masses first noted, but not considered a concern to O • OS periocular edema, blepharospasm, mucoid epiphora, exophthalmos, lack of retropulsion, firm superior and inferior eyelids, keratitis; OD WNL • OS superior eyelid biopsy: anaplastic carcinoma • Advanced imaging offered to O, respectfully declined • CT scan to evaluate for metastasis of previously diagnosed OS SCC, determine cause for lack of retropulsion, long term prognosis, and treatment planning • Tx: polymixin/bacitracin ophthalmic ointment and flunixin meglumine for exposure keratitis and pain/inflammation

5. History • October 2018 • Multiple firm, non-movable SQ masses • Not a primary concern to O, but agreed to punch biopsies for histopathology • Right pectoral and left shoulder mass biopsies: lymphohistiocytic dermatitis and panniculitis • Lymphoma vs. Pseudo-lymphoma??? • Recommended complete mass excision for best treatment recommendations, respectfully declined PHOTO COURTESY: Dr. Lynn M. Martin

6. History CBC • October 2018 • Complete blood count (CBC): • Anemia of chronic inflammation • Plasma biochemical profile (PBP): • WNL

7. Physical Examination at Presentation • February 2019 • Wt: 1490 lb • BCS: 6/9 • T: 99º F • HR: 36 bpm • RR: 16 brpm

8. Physical Examination at Presentation Numerous subcutaneous masses including the ventral neck, thorax and groin. Masses in the inguinal and medial thigh region were ulcerated and causing discomfort and edema after exercise. Enophthalmos and mucopurulent discharge OS PHOTO COURTESY: Dr. Lynn M. Martin

9. Physical Examination at Presentation Abnormalities: OS: enophthalmos, mucopurulent discharge, medial strabismus, lack of retropulsion OD: WNL PHOTO COURTESY: Dr. Kevin S. Donnelly

10. OD OS PHOTO COURTESY: Dr. Kevin S. Donnelly PHOTO COURTESY: Dr. Kevin S. Donnelly Enophthalmos Mucopurulent discharge Medial strabismus WNL

11. Physical Examination at Presentation • Abnormalities continued: • SQ masses • Firm, non-movable, haired • Multiple along ventral neck, thorax, abdomen, inguinal region, medial thigh, lateral shoulder and thigh • Single mass on left neck and right nasoincisive notch • 86 masses measured and body mapped • Few ulcerated along medial thighs • Sheath edema

12. PHOTO COURTESY: Dr. Lynn M. Martin PHOTO COURTESY: Dr. Lynn M. Martin • 86 SQ masses measured and body mapped • Firm, non-movable, haired • Multiple thorax, abdomen, lateral shoulder and thigh

13. PHOTO COURTESY: Dr. Lynn M. Martin • SQ masses - lateral shoulder PHOTO COURTESY: Dr. Lynn M. Martin

14. PHOTO COURTESY: Dr. Lynn M. Martin PHOTO COURTESY: Dr. Lynn M. Martin • SQ masses - lateral thigh

15. Sheath edema Inguinal region, medial thigh ulceration PHOTO COURTESY: Dr. Lynn M. Martin Nasoincisive notch PHOTO COURTESY: Dr. Lynn M. Martin PHOTO COURTESY: Dr. Lynn M. Martin

16. Problem List • Enophthalmia OS • Mucopurulent discharge OS • Medial strabismus OS • Lack of retropulsion OS • Carcinoma of superior eyelid OS • SQ masses – lymphohistiocytic dermatitis and panniculitis • Sheath edema PHOTO COURTESY: Dr. Lynn M. Martin

17. Differential Diagnoses Enophthalmos OS • Structural change to bony orbit • Retraction Mucopurulent discharge OS • Recurring SCC • Corneal ulcer • Keratitis Medial strabismus OS • Neurogenic atrophy of the lateral rectus muscle (CN VI dysfunction) Lack of retropulsion OS • Retrobulbar mass Carcinoma of superior eyelid OS • Metastasis of SCC SQ masses (lymphohistiocytic dermatitis and panniculitis) • Cutaneous lymphoma • Cutaneous pseudo-lymphoma Sheath edema • Impaired lymphatic drainage • Hypoproteinemia • Vasculitis

18. Initial Diagnostic Tests • CBC: • WNL • PBP: • Mild hyperglycemia (111 mg/dL; rr 77-107 mg/dL) • Stress • Mild hyperalbuminemia (3.8 mg/dL; rr 2.5-3.6 mg/dL) • Normal variant • PE, CBC and PBP did not support dehydration • Transabdominal and transthoracic ultrasonography: WNL

19. Outcome Due to decreased quality of use and life as a riding horse and long-term guarded prognosis of periorbital carcinoma, the O elected to donate the gelding to the University of Missouri for euthanasia and additional investigations.

20. Gross Postmortem Examination Gastric ulcers – incidental finding Squamous ulcers - Grade IV PHOTO COURTESY: Dr. Dae Young Kim Glandular ulcers – Pyloric mild flat diffuse erythematous lesions PHOTO COURTESY: Dr. Dae Young Kim

21. Gross Postmortem Examination PHOTO COURTESY: Dr. Dae Young Kim Some SQ masses were very focal and only associated with SQ tissue, while others invaded into the underlying skeletal muscle. PHOTO COURTESY: Dr. Dae Young Kim

22. Histopathology – Skin Mass Round tumor cells with mitoses (arrows) in a solid cellular sheet. H&E, x600 PHOTO COURTESY: Dr. Dae Young Kim

23. Histopathology – Skin Mass CD3 (T cell marker) CD79a (B cell marker) A B PHOTOS COURTESY: Dr. Dae Young Kim IBA1 (histiocyte marker) • A - Most of the round cells are CD3-positive T cells • B - Few of the round cells are CD79a-positive B cells • C - Scattered small number of cells are IBA1-positive histiocytic cells C

24. Gross Postmortem Examination Periocular mass OS OS abnormal tissue present circumferentially around the globe/within the bony orbit. This image illustrates the nasal and superior aspects of the tissue. PHOTO COURTESY: Dr. Dae Young Kim

25. Gross Postmortem Examination OS OD PHOTO COURTESY: Dr. Dae Young Kim Comparison of the right bony orbit to the left bony orbit. Note the enlarged orbital space of the left compared to the right.

26. Gross Postmortem Examination OD OS PHOTO COURTESY: Dr. Dae Young Kim The left eye and extraocular structures including muscles fat and abnormal tissue were significantly larger than the right side.

27. CT wo Contrast R There was a soft tissue attenuating, lobulated mass within the left retrobulbar space that displaced the left globe laterally and was intimately associated with the ocular musculature and left optic nerve. CT collected after head was severed from body postmortem

28. CT wo Contrast R Note dorsal deviation of the left cerebrum due to the left retrobulbar mass and risk of cerebral or dural invasion due to regional temporal bone destruction. The bony structure of the left frontoconchal sinus was also affected.

29. MRI wo Contrast R There was a lobulated mass T2 hypertense to the ocular muscles within the left retrobulbar space that displaced the left globe laterally. MRI collected after head was severed from body postmortem

30. Histopathology – Periocular Mass Skeletal muscle Optic Nerve Tumor H&E, x20 H&E, x400 There is a poorly demarcated, aggressively invasive neoplasm near the optic nerve. The neoplastic cells are individualized, round to polyhedral. The tumor cells are strongly positive for cytokeratin (arrows) by immunohistochemistry. Cytokeratin IHC, x600 PHOTOS COURTESY: Dr. Dae Young Kim

31. Additional Diagnostic Tests qPCR for Borreliaburgdorferi on fresh tissue Negative Indirect immunofluorescent assay for Borreliaburgdorferi on serum <1:40 Negative PCR for Equine Herpes Virus 2 & 5 Negative PCR for antigen receptor rearrangements (PARR) T cell and histiocyte-rich B cell lymphoma (non-epitheliotropic)

32. Final Diagnosis • T cell and histiocyte-rich B cell lymphoma (cutaneous masses) • Anaplastic carcinoma (retrobulbar mass) • Equine Gastric Ulcer Disease

33. Discussion – Lymphoma Affects all ages of life with no gender predilection 4 Types: • Generalized or multicentric • Alimentary • Mediastinal • Cutaneous (rare) Heterogenous in morphology and occasionally associated with hematologic abnormalities • Hyperfibrinoginemia, anemia, leukemia thrombocytopenia

34. Discussion – Cutaneous Lymphoma • Quarter Horse, Thoroughbred, Standardbred • Single to multifocal skin nodules with no other abnormalities • Epitheliotropic or non-epitheliotropic • Pruritus, ulceration and weeping yellow discharge • Can persist over many years and not progress • Reported median survival time ranges from 5 months to 11 years

35. Discussion – Cutaneous Lymphoma Treatment • Address underlying disease (EHV-5, Borrelia) • Surgical resection – typically reoccur • Corticosteroids • Chemotherapy

36. Discussion – Cutaneous Lymphoma Chemotherapy Cisplatin intralesional injections (Reed et al., 2018) Cyclophosphamide with autologous vaccine • Marked reduction in ventral edema and static nodule size (Gollagheret al., 1993) Lomustine (CCNU) with prednisolone • CCNU: alkylating agent that binds DNA and has cytotoxic, mutagenic and carcinogenic effects • Complete regression of tumor (Doyle et al., 2013)

37. Discussion – Carcinoma SCC is the most common neoplasm of the equine eye • Can affect the bulbar conjunctiva, corneal conjunctiva, third eyelid and eyelids • Typically locally invasive • Can invade the globe, bony orbit, regional lymph nodes, salivary glands or thorax

38. Discussion – Carcinoma Treatment • Surgical excision • Alone has a recurrence of 50-67% • Cryotherapy • Immunotherapy • Chemotherapy • Carbon dioxide laser ablation • Radiation • Photodynamic therapy • Periocular tumors; where PDT was the first and only treatment modality, recurrence rate was 0% within 1 year (Giuliano, et al., 2008)

39. Further Reading • Taintor S, Schleis S. Equine Lymphoma. Equine Veterinary Education. Equine vet. Educ.(2011)23(4) 205-213 • Giuliano E, MacDonald I, Dudley M, Dougherty T, Klauss G, Ota J, Pearce J, Johnson P. Photodynamic therapy for the treatment of periocular squamous cell carcinoma in horses: a pilot study. Veterinary Ophthalmology 2008; 11:27-34 • Doyle A, MacDonald V, Bourque A. Use of lomustine (CCNU) in a case of cutaneous equine lymphoma. Can Vet J 2013; 54: 1137-1141 • Gollagher R, Ziola B, Chelack B, Haines D. Immunotherapy of equine cutaneous lymphosarcoma using low dose cyclophosphamide and autologous tumor cells infected with vaccinia virus. Can Vet J 1993: 34:371-373 • Reed S, Bayly, W, Sellon D. Cutaneous Lymphoma. In: Equine Internal Medicine, 4th ed. Ed: Reed S. Elsevier Inc., St. Louis, Missouri, USA. 2018 Pp. 1210.

40. Acknowledgements Equine Internal Medicine Kile S. Townsend, DVM Lynn M. Martin, DVM, MPH, DACVIM (LAIM) Ophthalmology Elizabeth Schaefer, DVM Kevin S. Donnelly, DVM, MS, DACVO Radiology James Karnia, DVM Jimmy C. Lattimer, DVM, MS, DACVR (Radiology and Radiation Oncology) Oncology Lindsay Donnelly, DVM, MS, DACVIM (Oncology) Pathology Dae Young Kim, DVM, PhD, DACVP (Pathology) Student peers, technicians, barn crew, medical records/office staff LeukocyteAntigenBiologyLaboratory – UC Davis

41. Questions?