Presumed primary intraocular chondrosarcoma in cats

Abstract

Following unilateral enucleation, 4 Domestic Shorthair cats with an average age of 12.5 years (range: 9-16 years) were histologically diagnosed with a presumed primary intraocular chondrosarcoma at the Comparative Ocular Pathology Laboratory of Wisconsin (Madison, Wisconsin). Medical records and follow-up were available for 3 of the 4 cats. Clinically, only 1 eye was affected in each cat; a mass lesion was noted in 2 cats, and a neoplasm was suspected in the other 2 cats. Grossly, 3 tumors presented as coalescing, poorly demarcated, white, friable masses filling the vitreous and intraocular chambers; 1 tumor presented as a solitary, well-demarcated, tan mass involving the iris and ciliary body. Histologically, all 4 neoplasms were composed of haphazardly arranged plump neoplastic spindle cells surrounded by irregular islands and thick trabeculae of abundant, variably basophilic, and Alcian blue-positive chondromatous matrix. None of the cats presented histologically or clinically with signs suggestive of feline posttraumatic ocular sarcoma. Two cats are still alive and healthy 6 months and 3 years following enucleation. One cat died 6 months following enucleation; however, this cat suffered from poorly controlled diabetes mellitus, and the cause of death is undetermined. No other tumors or skeletal lesions were identified that could suggest a metastatic tumor to the eye. The origin of primary intraocular chondrosarcoma is unclear, but is presumed to be ocular multipotent mesenchymal stem cells. Four cases of intraocular chondrosarcoma in cats not associated with the posttraumatic sarcoma complex of intraocular tumors are described.

Presumed post‐traumatic ocular chondrosarcoma with intrathoracic metastases in a cat

“…Secondary rather than primary involvement of the eye was ruled out by the absence of a potential primary single neoplastic lesion elsewhere in the body and the multifocal neoplastic involvement of the tissues of the thoracic cavity, characteristic of metastatic spread. The diagnosis of post‐traumatic ocular chondrosarcoma was supported by the presence of intralesional remnants of a ruptured lens capsule, interpreted as evidence of ocular trauma . Ocular trauma with lenticular damage is a significant risk factor for the development of ocular sarcoma .…”

“…The diagnosis of post-traumatic ocular chondrosarcoma was supported by the presence of intralesional remnants of a ruptured lens capsule, interpreted as evidence of ocular trauma. 3 Ocular trauma with lenticular damage is a significant risk factor for the development of ocular sarcoma. 6 This unique neoplastic entity has been reported almost exclusively in cats, 10 except for two cases in rabbits.…”

“…In the database of the same laboratory, 4800 of 9000 feline samples were neoplasms, including 16 chondrosarcomas. Of these, four were presumed to be primary and 12 post‐traumatic based on the absence and presence, respectively, of histological changes consistent with a previous traumatic ocular event …”

“…A lower proportion of these tumors are seen in the subcutaneous tissue, some of which are related to vaccination. 1 Ocular chondrosarcoma in cats has been reported as either primary, in the absence of changes indicative of previous lesions in the eye, 2,3 or secondary to trauma. 4,5 According to a recently published case series of presumed primary, nontrauma-related intraocular chondrosarcomas in cats, 3 some of the previously reported cases of intraocular chondrosarcoma classified as primary could actually have been secondary, as post-traumatic ocular sarcoma had not yet been identified as a separate entity at the time of their diagnosis.…”

“…Of these, four were presumed to be primary and 12 post-traumatic based on the absence and presence, respectively, of histological changes consistent with a previous traumatic ocular event. 3 Metastasis of intraocular neoplasms is rarely reported, with most of these tumors considered to have only minor potential for metastatic spread. 10 Of the post-traumatic ocular sarcomas, the spindle cell variant can be highly infiltrative locally, with possible invasion of the brain via the optic foramen; however, the incidence of distant metastases is unknown for this and the other variants of this type of neoplasm.…”