Epitheliotropic Lymphoma of the Nasal Skin

Background: Cutaneous epitheliotropic T cell lymphoma is a malignant neoplasm of atypical T lymphocytes infiltrating the epidermis and dermal adnexa. Although uncommon in general veterinary practice, it tends to pursue an aggressive clinical course and is easily mistaken for inflammatory or traumatic skin diseases. Early lesions are often present as ulcerated or crusted plaques that resemble severe dermatitis or injuries, which can delay recognition and diagnosis. This report describes clinical presentation, histopathological characteristics and immunohistochemical findings of an eight-year-old castrated male Pekingese dog with a firm and centrally ulcerated subcutaneous nasal mass. Methods: An excisional biopsy was obtained. The tissue was routinely processed and stained with hematoxylin and eosin. CD۳ and Ki۶۷ immunohistochemistry was undertaken to determine T cell origin and proliferative index. Results: Histological examination revealed dense infiltrates of small to medium sized pleomorphic lymphocytes invading the epidermis and adnexal structures. Epidermal ulceration and pustule formation were also evident. Immunohistochemistry demonstrated diffuse cytoplasmic CD۳ expression in the neoplastic cells and a Ki۶۷ index of roughly ۴۰ %, consistent with an actively proliferative T cell neoplasm. Histopathologic and immunohistochemical findings supported the diagnosis of cutaneous epitheliotropic lymphoma. Further evaluation of peripheral blood and lymph nodes was recommended to rule out Sézary syndrome. Conclusion: This case illustrates an ulcerative presentation of epitheliotropic T cell lymphoma in a small breed dog. Awareness of this pattern is important because it can clinically mimic immune mediated or traumatic skin disease. A combination of gross examination, histopathology and immunohistochemistry facilitate accurate diagnosis and guides clinical management, although the prognosis for affected dogs remains guarded.

کلیدواژه ها:

Dog ، Epitheliotropic lymphoma ، Immunohistochemistry ، Surgical pathology