Page 717 - Withrow and MacEwen's Small Animal Clinical Oncology, 6th Edition

CHAPTER 33 Hematopoietic Tumors 695

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• Fig. 33.6 (A) Early epitheliotropic cutaneous lymphoma in the scaly, plaque stage in a dog. (B) Advanced
epitheliotropic cutaneous lymphoma in the nodular stage in a dog. (C) Oral mucosal epitheliotropic cutane-
ous lymphoma in a dog.
hypopigmentation and alopecia. Epitheliotropic T-cell lymphoma involve secondary extension into the CNS. Most have a B-cell
(e.g., mycosis fungoides) typically has a clinical course with three immunophenotype and have meningeal, perivascular, and peri-
apparent clinical stages. Initially, there will be scaling, alopecia, ventricular locations, whereas T-cell varieties are more likely to
and pruritus (Fig. 33.6A), which can mimic a variety of other skin involve the peripheral nerves. 136 Seizures, paralysis, and paresis
conditions. As the disease progresses, the skin becomes more ery- may be noted.
thematous, thickened, ulcerated, and exudative. The final stage is Ocular lymphoma is characterized by infiltration and thick-
characterized by proliferative plaques and nodules with progres- ening of the iris, uveitis, hypopyon, hyphema, posterior syn-
sive ulceration (Fig. 33.6B). Oral mucocutaneous involvement echia, and glaucoma, and is discussed in more detail in Chapter
may also occur and this can appear as multicentric erythematous 32. 137–139 Although it is often secondary to multicentric systemic
plaque-like hypopigmented lesions or nodules associated with the lymphoma, in a compilation of 100 cases, 61% were presumed
gum and lips (Fig. 33.6C). Extracutaneous involvement can also solitary ocular lymphoma (PSOL) without systemic involvement
occur, most often in the LNs, spleen, liver, and bone marrow/ at diagnosis and no progression postenucleation. 137 Peripheral
peripheral blood. Nonepitheliotropic cutaneous lymphomas are T-cell lymphoma and DLBCL are the most common subtypes.
also quite variable in appearance and can form single or multiple Importantly, dogs with PSOL had median survival times (MSTs)
dermal or subcutaneous nodules or plaques that may be nonpu- of 769 days versus 103 days for dogs having systemic involvement
71
ritic, ulcerated, or alopecic with crusts. The face (lips, nasal pla- at diagnosis. In one study of 94 cases of canine multicentric lym-
num, eyelids), lower extremities (paws, interdigital folds), neck, phoma, 37% had ocular changes consistent with lymphoma; and,
and trunk are often affected. in a series of 102 cases of uveitis in dogs, 17% were secondary to
Dogs with CNS lymphoma may be presented with either lymphoma. 139 Anterior uveitis was most commonly seen in the
multifocal or solitary involvement. 133–135 The majority of cases advanced stage of disease (stage V).