Abstract
Purpose: :
Intravascular lymphoma is a rare, usually fatal, cancer reported in humans and dogs. Involvement of the eye in dogs has been reported but we present a series of cases first recognized as ocular disease and suggest changes in terminology based on our findings.
Methods: :
Over 5,600 cases of canine ocular neoplasia seen at the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) were searched for cases with an intravascular round cell tumor. Microscopic evaluation was performed, the presenting findings were recorded, and the final outcome was obtained by phone interview. The neoplastic cells were characterized with the following battery of immunohistochemical stains: CD3, CD79a, CD18, and MHC-II.
Results: :
Eight cases met the inclusion criteria.These included 2 Rottweilers, 1 Foxhound, 1 Akita and 4 mixed breed. The mean age was 5.5 years, with a range from 1 to 10 years. Gender included 1 female, 4 female spayed, and 3 male neutered. In all dogs the tumors were primarily seen in blood vessels in the anterior and posterior uvea. All dogs for which follow-up information was obtained were dead within a 2 month period. 6 of 8 tumors were strongly positive for both CD18 and MHC-II. Of the two tumors negative for both CD18 and MHC-II, one stained positive for CD3 and the other for CD79a. Among the tumors positive for CD18 and MHC-II, 2 were also positive for CD3, 1 was positive for Cd79a, 2 were positive for both CD3 and CD79a, and a final case was negative for CD3 with the CD79a stain un-interpretable.
Conclusions: :
Canine intravascular round cell tumor is a rare, fatal, tumor over represented in the eye. Based on cellular phenotype the neoplastic cells most often express markers suggesting a phagocytic lineage. For that reason the tumors in dogs differ from the similar tumor, intravascular lymphoma, in humans. One of 8 tumors in this series was purely intravascular and purely of B-cell lineage, both features of intravascular lymphoma.
Keywords: tumors • uvea • pathology techniques