Page 1232 - Problem-Based Feline Medicine

1224 PART 15 CAT WITH EYE PROBLEMS

because the eyelids cannot close, and the tear film
CONJUNCTIVAL LYMPHOSARCOMA
cannot cover the surface.
Classical signs The third eyelid may be involved. Swelling and partial
prolapse may result in abnormal prominence of the
● Swollen, thickened conjunctiva covered
third eyelid.
with dry crusty discharge.
● Very little redness (hyperemia). There may be involvement of the orbital tissues. This
● Globe may be prominent caused by will cause swelling of the conjunctiva and a prominent
involvement of orbital tissue. globe (exophthalmos).
● Third eyelid may be swollen and
prominent.
Diagnosis
See the main reference on pages 1078, 1311 (The Cat Cytology from a fine-needle biopsy should reveal
With Lumps and Bumps and The Cat With Abnormal large numbers of plump lymphoid cells with a large
Globe Position or Size). dark staining nucleus, and prominent nucleoli.
Fine-needle aspirates from enlarged lymph nodes
will help to support a diagnosis. (See page 1075.)
Pathogenesis
Histopathology will show a similar infiltration of neo-
The conjunctiva has a rich supply of lymphoid tissue, plastic cells in the conjunctiva.
but it usually becomes affected secondary to orbital
Serology for FeLV is positive in many cases. (See
or systemic lymphosarcoma.
page 1142.)
The condition may appear acutely, and frequently the
Hematology may be useful to support a diagnosis.
cat will show no other systemic signs such as swollen
Occasionally neoplastic lymphoid cells are prominent
lymph nodes or enlarged spleen.
in the blood smear, especially if there are greatly
Focal and diffuse lesions have been reported. increased numbers of lymphocytes.
Infiltration of the conjunctiva with neoplastic cells
Ocular ultrasound using a 10-MHz probe will help
causes swelling.
identify focal lesions in the orbit. Ultrasound-guided
There may be a mild mucopurulent discharge. The biopsies can be done by guiding a Tru-cut biopsy probe
discharge crusts on the conjunctival surface as it into the affected area.
becomes dry and inflamed, which results from lack of
tear lubrication caused by the swelling and poor abil-
Treatment
ity to blink.
Eye lubricants and artificial tears are required to
lubricate swollen and dry conjunctiva, and help to
prevent secondary complications such a corneal ulcer-
Clinical signs
ation.
This is a rare condition in cats.
Topical corticosteroid drops may be indicated as an
Focal or diffuse swelling of the conjunctiva is seen. adjunct to systemic therapy. Prednisolone acetate 1% or
The swelling has the same appearance as chemosis, dexamethasone 0.1% drops instilled into the eye three
however, the conjunctiva is not edematous, but infil- to four times a day will help reduce swelling associated
trated by neoplastic lymphoid cells. There is very little with neoplastic infiltration.
redness (hyperemia) present.
Chemotherapy may be effective in achieving remis-
The swollen conjunctiva may be dry, and have a sion in some cats. (See The Cat With Signs of Chronic
crusty mucopurulent discharge on the surface, Small Bowel Diarrhea, page 742.)