Small Animal Dermatology, 3rd edition

CHAPTER 24 EPITHELIOTROPIC LYMPHOMA 369

Dermal infiltrate: polymorphous; in the patch and plaque stages, limited to the

superficial dermis; in the nodular stage, extends to the deep dermis and subcutis

Epitheliotrophism of neoplastic lymphocytes: usually remains prominent

throughout all stages

Immunohistochemistry for CD3 expression and T cell antigen receptor gene

rearrangement analysis staining may be required to differentiate CEL from reac-

tive cutaneous histiocytosis.

THERAPEUTICS

Drugs of Choice

 CnEL:
Cyclophosphamide-doxorubicin-vincristine-prednisolone (CHOP) protocols
L-asparaginase-CHOP protocols
Vincristine-cyclophosphamide-prednisolone (COP) protocols
Vinblastine
Chlorambucil-prednisolone
Lomustine (CCNU)
Consultation with a veterinary oncologist for treatment options recommended.

 CEL:
Lomustine (CCNU): several studies published in the veterinary literature indi-

cate an overall response rate of 80%, with complete remission achieved in about

25% of cases (60–70 mg/m^2 PO every 3–4 weeks for a mean of 3–5 treatments);

myelosuppression and hepatoxicity (Figures 24.17, 24.18)

High-dose linoleic acid (e.g., sunflower oil): 3 mL/kg PO twice weekly demon-

strated improvement in seven of 10 dogs for up to 2 years

Dacarbazine (1000 mg/m^2 intravenous over 4–8 h every 2–3 weeks) for three

treatments; gastrointestinal toxicity; myelosuppression

CHOP protocols

Topical chemotherapy: mechlorethamine (nitrogen mustard) some success in

managing early lesions but lack of long-term efficacy; carcinogenic potential for

human beings

Corticosteroids: topical and/or systemic may result in symptomatic relief

Retinoids: isotretinoin (3 mg/kg PO q24h) or acitretin (2 mg/kg PO q24h) may

be beneficial; cost can be a limiting factor; extreme teratogen; do not use in intact

females because of severe and predictable teratogenicity and the extremely long

withdrawal period; women of child-bearing age should not handle this medica-

tion

Imiquimod: a topical immunomodulator with antineoplastic and antiviral

effects; may be useful for localized disease; no published reports in veterinary

literature