Canine Ocular Intravascular Lymphoma:

Lassoing a Rare Tumor

Chuck Schobert, DVM, MS

COPLOW, University of Wisconsin School of Veterinary Medicine

Introduction

• Rare, fatal canine cancer

• Humans, too• Previous canine

ocular reports• Five cases, first

presented as ocular disease

• Terminology change?

Human Intravascular Lymphoma (IVL) vs Canine IVL

• In general:– Multiple tissues– Despite vessels engorged with tumor cells,

they still do not circulate (ie, can’t diagnose with CBC or bone marrow aspirate)

– Proliferation as clusters in vessels with attachment to endothelium

– Veins more than arteries

Human IVL

• B cell lymphoma

• AKA, angiotrophic or malignant endotheliomotosis

• Only one ocular report

• Cutaneous most common

• Only one report of tumor of phagocytic origin

Canine IVL

• Wide variety of tissues, 6/23 ocular

• A variety of IHC markers were examinedB cell lineage rareT cell lineage more commonOther IHC markers of non-lymphoid origin such as

those for histiocytic or macrophage antigens rarely used

Methods

• Over 5,600 cases of canine ocular neoplasia surveyed in COPLOW

• Searched for intravascular round cell tumors

• H & E slides evaluated microscopically

Inclusion Criteria

• Clusters of cells in vessel lumen

• Dark-staining, irregular nuclei, scant cytoplasm

• Adherent as clusters or rafts of cells

• Attachment to vessel endothelium

• Excluded three IVL lymphoma cases that did not meet these criteria

Phone Follow-up

• Survival time• Metastatic disease• Original presentation• Treatment?• If necessary and

permissable, rDVM and owners were contacted

Immunohistochemistry

• CD3/T cell

• CD79a/B cell

• CD18 & MHC-II/macrophage Not exlusive for macrophage Used routinely for cells of histiocytic or macrophage origin

Hemotoxylin and Eosin

Hemotoxylin and Eosin

Case # Age/Breed

Gender

CD18 MHC-II CD3 CD79a

07RD1777 2/Lab/MN ++ ++ + -

06RD906 4/DobieX/MN ++ ++ + +

04RD0193 10/Chow-Lab/FS ++ ++ Weak + +

03RD1291 9/Foxhound/FS ++ ++ - -

93RD021 3/Akita/FS ++ ++ + +

Immunohistochemistry

CD3 CD79a

CD18 MHC-II

Immunohistochemistry

• 5/5 CD18 and MHC-II positive

• 3/5 T cell+, B cell +

• 1/5 T cell+ (CD3 +, CD79a -)

• 1/5 T cell-, B cell- (CD3-, CD79a-)

Discussion

• Found in variety of tissues• Rare tumor over-represented in the eye• Staining characteristics=macrophage

lineage• IV Lymphoma from human studies shows

distinct features of a true lymphoma lineage

• Propose new name in canines: Intravascular Histiocytic Tumor

Acknowledgements

• Dr Dick Dubielzig

• Dr Howard Steinberg

• Dr Christiane Kafarnik

• Kate Lieber

• Histopath Laboratory