Page 1212 - Cote clinical veterinary advisor dogs and cats 4th

604.e4 Lymphoma, Central Nervous System

compared with gray matter. Perilesional prednisone). Several protocols exist (pp. of up to 7 months. Cats treated with
hyperintensity is common. 602 and 603). radiation therapy and chemotherapy
VetBooks.ir meninges around the lesion, and one-half prednisone can exert an effect across an ○ Older studies of cats with spinal lym-
tended to have a better outcome.
Of these drugs, only L-asparaginase and
○ The majority of lesions have abnormal
■
have generalized contrast enhancement.
phoma have reported remission rates
intact blood-brain barrier.
• CT or CT/myelogram (for spinal lesions)
can be considered if MRI is not available. ■ Tumor microvasculature has greater of 50% and median response durations
of 3-5 months, but treatment protocols
permeability than the normal blood-
• Radiography: limited utility brain barrier. Penetration of the other were not as aggressive as those currently
○ Skull radiographs are not routinely drugs into CNS lymphoma is unknown recommended and up to 90% were FeLV
recommended. and likely varies. seropositive.
○ Plain vertebral radiographs usually are • CCNU (lomustine) crosses the blood-brain
normal, but purely lytic lesions occasion- barrier and achieves therapeutic levels within PEARLS & CONSIDERATIONS
ally are seen. Radiographs can be helpful the CNS. For lymphoma infiltrating the
for ruling out osseous tumors. CNS parenchyma, it is commonly used Comments
• Cerebrospinal fluid (CSF) analysis with L-asparaginase and possibly the other If a cat tests positive for FeLV or FIV, the owner
○ CSF consistently has an elevated protein CHOP drugs. should be educated about these diseases, and all
count. ○ Cytosine arabinoside (Cytosar, cytarabine) other cats in the household should be tested.
○ Nucleated cell count can be normal or and procarbazine also penetrate the blood-
increased. A mixed-cell pleocytosis is most brain barrier, but they have only modest Technician Tips
common. activity against other, more common forms Status epilepticus (continuous seizure activity
Neoplastic lymphoblasts are identified of lymphoma. for > 5 minutes) and cluster seizures (≥ 2
■
in < 50% of affected patients. ○ Single-agent prednisone may be used for seizures in 24 hours) are medical emergencies.
Polymerase chain reaction (PCR) for palliative treatment. Clients should be advised to bring their pets
■
antigen receptor rearrangement (PARR) • Radiation therapy in combination with che- to a veterinary hospital immediately.
can be considered, but results are dif- motherapy may rapidly shrink compressive
ficult to interpret because DNA yield tumors. SUGGESTED READINGS
is often low. A positive result would be • Radiation treatment fields may be focal for Marioni-Henry K, et al: Tumors affecting the spinal
strongly supportive of lymphoma, but solitary lesions or can include the entire cord of cats: 85 cases (1980-2005). J Am Vet Med
a negative result cannot rule it out. brain and/or spinal cord in patients with Assoc 232:237-243, 2008.
• To reach a definitive diagnosis, histopatho- multicentric or diffuse CNS involvement. Palus V, et al: MRI features of CNS lymphoma in
logic or cytologic analysis is required. For • Surgery is indicated only when a biopsy is dogs and cats. Vet Radiol Ultrasound 53:44, 2012.
CNS lesions, this usually requires surgery needed to confirm the diagnosis of lymphoma Siseo S, et al: Canine nervous system lymphoma
or specialized equipment (fluoroscopy, or when rapid decompression of the brain or subtypes display characteristic neuroanatomical
patterns. Vet Pathol 54:53, 2017.
stereotactic biopsy). Whenever possible spinal cord is needed and radiation therapy Snyder JM, et al: Secondary intracranial neoplasia
(e.g., secondary CNS lymphoma), obtain- is unavailable. in the dog: 177 cases (1986-2003). J Vet Intern
ing samples from other affected organs is Med 22:172-177, 2008.
preferable. PROGNOSIS & OUTCOME Snyder JM, et al: Canine intracranial primary
neoplasia: 173 cases (1986-2003). J Vet Intern
TREATMENT • There is little information regarding the Med 20:669-775, 2006.
prognosis for dogs with CNS lymphoma. Troxel MT, et al: Feline intracranial neoplasia:
Treatment Overview ○ When treated with systemic chemotherapy, retrospective review of 160 cases (1985-2001). J
Optimal treatment regimens are not yet known. with or without radiation therapy, dogs Vet Intern Med 17:850-859, 2003.
Definitive treatment centers on systemic che- have had reported survival times of 1-3
motherapy, but drug selection is controversial months. RELATED CLIENT EDUCATION
due to concerns about the blood-brain barrier. ○ In the author’s experience, when dogs SHEETS
Radiation therapy (and rarely, surgery) may present with CNS signs at the time of
help rapidly resolve neurologic abnormalities. initial diagnosis, survival times of up to Consent to Administer Chemotherapy
6 to 12 months are possible. In contrast, Consent to Perform Bone Marrow Biopsy
Acute General Treatment when dogs first demonstrate CNS signs Consent to Perform Cerebrospinal Fluid Tap
• The majority of CNS lymphomas are second- at the time of relapse, prognosis is very Consent to Perform Computerized Tomography
ary, and systemic chemotherapy remains the guarded, and survival times are almost (CT Scan)
mainstay of therapy. uniformly < 1-3 months. Consent to Perform Fine-Needle Aspiration
○ For the more common multicentric • In cats with various forms of lymphoma of Masses
forms of lymphoma not involving the (including CNS involvement), anatomic Consent to Perform Radiation Therapy
CNS, the protocols used most often location does not appear to be a prognostic Lymphoma, Peripheral or Multicentric
include the drugs L-asparaginase, and factor. However, testing positive for FeLV is AUTHOR: Dennis B. Bailey, DVM, DACVIM
the drugs used in CHOP protocols (i.e., consistently a negative prognostic factor. EDITOR: Kenneth M. Rassnick, DVM, DACVIM
vincristine [Oncovin], cyclophosphamide, ○ Studies looking specifically at cats with
doxorubicin [hydroxydaunoru bicin], and brain lymphoma reported survival times

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