Abstract
Purpose::
Feline ocular post-traumatic sarcoma (FOPTS) is a recognized entity. Until now most descriptions of this entity have been of a spindle-cell variant which arises from the neoplastic transformation of lens epithelial cells. The aim of this study is to characterize a new variant of FOPTS, the round cell variant.
Methods::
7 cases diagnosed as round cell variant of FOPTS were selected from the Comparative Ocular Pathology Laboratory of Wisconsin. Signalment, history, clinical signs and histopathological features were recorded, and immunohistochemistry (IHC) for B cell (CD79a) and T cell (CD3) markers was performed.
Results::
4 Domestic Short Haired, 2 Domestic Long Haired and 1 Abyssinian cat were included in the study. Mean age at enucleation was 11.8 years. There were 5 neutered males and 2 spayed females. Right eye was affected in 5 cases and left eye was affected in 2 cases. History of trauma was provided in 2 cases. Histopathological evidence of lens capsule rupture was found in 5 cases, while in the remaining 2 the lens rupture could not be documented but was suspected based on the wrinkled lens capsule. The main microscopic features of the tumor were: 1. Neoplastic round cells arranged in solid sheets circumferentially around the eye, 2. A pattern of survival of tumor cells around blood vessels, and 3. Extensive coagulation necrosis of tumor tissue away outside the zone of perivascular survival. Retinal tissue was necrotic in all of the cases. On IHC, all 7 cases were positive for both the B cell marker and the T cell marker.
Conclusions::
The traumatized feline globe is at risk of developing several distinctly different neoplasms. The spindle cell variant has been previously described but the round cell variant is described here for the first time. These are tumors of lymphocytes and have a distinctive distribution in the traumatized globe suggesting that the tumor first develops in the globe.
Keywords: tumors • trauma • pathobiology