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Intraocular Neoplasia 559

TREATMENT • Cerebral edema: prednisone 0.5 mg/kg PO • There are no large-scale reports of survival
q 12h initially, then taper to lowest dose that times for cats, with the exception of menin-
Treatment Overview
VetBooks.ir Definitive treatment involves surgical excision Drug Interactions However, the long-term prognosis for cats Diseases and Disorders
can control clinical signs
giomas (average survival time is 2 years).
and/or radiation therapy and/or chemotherapy.
with other brain tumors is likely similar to
Acute General Treatment • Drug interactions or altered metabolism of that for dogs.
medications have been reported between
• Surgical excision: used for removing or corticosteroids and amphotericin B, furo- PEARLS & CONSIDERATIONS
debulking the tumor if accessible and for semide, thiazide diuretics, digitalis glycosides,
providing a definitive histologic diagnosis cyclosporine, phenytoin, phenobarbital, and Comments
• Radiation therapy: used as adjunctive treat- mitotane. With neoplasia of the brain, asymmetrical neu-
ment to surgery or as a primary treatment • Corticosteroids should not be given concur- rologic deficits are much more common than
modality (conventional radiation therapy or rently with nonsteroidal antiinflammatory symmetrical deficits. Symmetrical neurologic
stereotactic radiosurgery); palliative radiation drugs or other potentially gastric ulcerogenic deficits make other diagnoses more likely.
therapy may be pursued to improve quality medications.
of life if full-course radiation therapy cannot • Phenobarbital may cause excessive sedation Prevention
be performed in dogs with intracranial mass lesions, even No known method to prevent disease
• Chemotherapy: most agents are not very at low doses.
effective because the blood-brain barrier Technician Tips
(BBB) prevents chemotherapeutic agents Possible Complications Postoperative craniotomy patients are very
from entering the brain. The exception is Progression of clinical signs, including status vulnerable to brain trauma, and comprehensive
nitrosourea drugs. epilepticus, brain herniation, and sudden care (e.g., padding of cage walls, prevention
○ Nitrosourea agents such as lomustine death of self-trauma through gentle restraint and
2
(CCNU 60-90 mg/m PO q 4-6 weeks) padding over the surgical site) can make the
2
or carmustine (BCNU 50 mg/m IV q Recommended Monitoring difference between an excellent outcome and
6 weeks) (p. 609), which can cross the • Serial neurologic exam every 4-6 weeks a life-threatening complication.
BBB, appear to have some effect in canine • Serum phenobarbital level 2 weeks after
gliomas and canine CNS lymphoma. starting medication, any change in dosage, Client Education
○ The most serious potential adverse effects or immediately after loading dose (p. 1372) • Warn owner about corticosteroid side effects
are myelosuppression (anemia, thrombocy- • Serum bromide (KBr) level 3-4 months after (e.g., polyuria, polydipsia, polyphagia, weight
topenia, leukopenia) and hepatotoxicosis. starting medication or after any change in gain, gastrointestinal ulceration).
○ Hydroxyurea 20 mg/kg PO q 24h can dosage for dogs; 2 months after starting • Phenobarbital and KBr: short-term side
significantly increase survival times for treatment in cats or immediately after loading effects include sedation/lethargy and pelvic
dogs with meningiomas compared with dose (p. 1319) limb weakness and ataxia. Long-term side
use of prednisone alone. Side effects at effects include polyuria, polydipsia, polypha-
this dose are typically mild. Monitor PROGNOSIS & OUTCOME gia, and weight gain. Less common adverse
CBC weekly initially and then CBC/ effects include hepatotoxicosis and blood
biochemical profile every 4 months. • In general, the prognosis is fair to guarded dyscrasias for phenobarbital and pancreatitis
• Cluster seizures or status epilepticus (p. 903) for dogs and cats. for KBr.
• Cerebral edema/brain herniation: mannitol • For dogs, several small-scale reports have
0.5-1.0 g/kg IV slowly over 15-20 minutes shown a median survival time of approxi- SUGGESTED READING
or hypertonic saline (7%-7.5%) 2-4 mL/kg mately 2-4 months with supportive care and Dewey CW: Encephalopathies: disorders of the brain.
IV slowly over 15-20 minutes nonspecific treatment only, 6-12 months with In Dewey CW, et al, editors: Practical guide to
surgery alone, 7-24 months with radiation canine and feline neurology, ed 3, Ames, IA, 2015,
Chronic Treatment therapy alone, 6 months to 3 years with Wiley-Blackwell, pp 141-236.
• Seizures: anticonvulsants should be used if surgery and radiation, and 7-11 months with AUTHOR: Mark T. Troxel, DVM, DACVIM
there is more than one seizure every 2-3 chemotherapy alone. EDITOR: Karen R. Muñana, DVM, MS, DACVIM
months; see p. 903 for treatment options.

Intraocular Neoplasia Client Education
Sheet

BASIC INFORMATION • Secondary intraocular neoplasia occurs • Primary intraocular sarcoma (feline ocular
through metastasis or (rarely) by extension posttraumatic sarcoma) occurs in cats of
Definition from adjacent tissues. any age.
• Primary intraocular neoplasms arise from the Epidemiology • Lymphoma is the most common neoplasm to
vascular intraocular tunic (uvea: iris, ciliary metastasize to the eye. Others include mas-
body, choroid) or limbal melanocytes. In cats, SPECIES, AGE, SEX tocytoma, chondrosarcoma, osteosarcoma,
primary intraocular sarcoma arises from an • Melanoma/melanocytoma affects dogs and carcinoma.
undetermined cell population, most likely and cats, usually older adults (>7 years),
lens epithelium. Neoplasia of the fibrous although are also seen in young dogs < 4
tunic, adnexa (eyelids, conjunctiva, lacrimal years old. GENETICS, BREED PREDISPOSITION
glands), and orbit are covered in additional • Medulloepithelioma usually affects animals Uveal melanoma and limbal melanoma have
detail on pp. 644 and 716). 1-4 years of age. demonstrated genetic predisposition in Labrador

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