Perforin Expression in Feline Epitheliotropic Cutaneous Lymphoma

Abstract

Abstract. Cutaneous lymphomas are uncommon in people and companion animals. The tumors can be broadly categorized into epitheliotropic and nonepitheliotropic forms, which appear to have different biological behaviors. The present case describes a feline cutaneous epitheliotropic lymphoma. Masses in a 9-year-old cat were first identified on the tail. The cat was treated with chemotherapy, but additional skin masses developed on the flank, face, and ears. Local radiation induced transient tumor regression, but eventual dissemination prompted euthanasia 13 months after initial tumor appearance. Granular lymphocytes were consistently detected on blood smears, and histologically, the tumor involved the skin and superficial subcutis. Tumor lymphocytes expressed cluster of differentiation 3 (CD3) and perforin molecules, suggestive of a cytotoxic phenotype. Location, histopathological features, and perforin expression were similar to a distinct entity in human medicine designated primary cutaneous, CD8-positive, epidermotropic, cytotoxic, T-cell lymphoma.

Cutaneous epitheliotropic T‐cell lymphoma in the cat: a review of the literature and five new cases

“…Lymphoma is the most common malignancy in the cat, representing one‐third of all tumours, 11 although cutaneous involvement only occurs in 1.76% of cases 12 . Only seven cases of feline CETL have been documented previously 5–10 . The signalment of those historical cases was consistent with that of the five new cases documented here (Table 1).…”

“…The follicular osteal epithelium was mildly, but consistently affected in cats. Dermal lymphocytic infiltration was reported in three of the seven historical feline cases reported, 6,8,10 and in four of our five new cases. In two of these new cases, there was greater infiltration of the dermis than the epithelium (nodular stage).…”

“…A history of chronic dermatitis before the development of CETL has also been proposed in dogs, 21–23 but a recent study of 25 cases of canine CETL did not report prior chronic dermatitis in any patient 2 . For the historical feline cases, 5–10 the median time between the onset of first lesions until the final diagnosis of CETL was 3.5 months (range 2.5–10 months, n = 4). In the cases reported in our study, the owners always described the cats as having a long history of slowly progressive dermatitis, but a relationship with a possible chronic inflammatory process was impossible to verify.…”

“…Cutaneous epitheliotropic T‐cell lymphoma (CETL) is well described in dogs, but the disease is rarely reported in the cat 1–4 . Only seven cases of feline CETL have been documented 5–10 . Cutaneous epitheliotropic T‐cell lymphoma is characterized in all species by cutaneous infiltration of neoplastic T lymphocytes with tropism for the epidermis and adnexal epithelium 1–4 .…”

Large granular lymphoma in six cats

“…LGLs originate from T cytotoxic (CD3 positive) or natural killer (CD3 negative) lymphocytes, cells which normally have cytoplasmic granules, containing various biologically active substances including granzyme, perforins, acid phosphatase and others (Kariya et al 1997, Neta et al 2008, Tsuboi et al 2010). In the majority of cases LGLs develop in intestinal mucosa producing segmental enlargement of the intestine, which with time progress into a tumoral mass easily detected during clinical examination.…”