title: Cutaneous epitheliotropic T-cell lymphoma with systemic dissemination in a dog.
abstract: Cutaneous epitheliotropic T-cell lymphoma (CETL) is characterized by neoplastic T-cell infiltration of the epidermis, adnexal structures, and oral mucosa. The objective of this report was to describe the pathological findings of a canine case of terminal-stage CETL. A 10-year-old, mixed-breed, neutered male dog was presented with erosion of the oral mucosa and mucocutaneous junction. The dog was diagnosed with CETL with no evidence of metastasis. Despite chemotherapy, the dog was re-presented with oral pain, vomiting, and diarrhea, and died 17 months after the first visit to the hospital. A complete autopsy was performed. Histologic examination of the primary lesion and systemic organs was performed. Gross examination revealed an advanced-stage oral lesion. Distinct tumor formation was not observed in the primary sites and systemic organs. Histologically, the primary oral lesion was characterized by massive intraepithelial infiltration of a large number of neoplastic lymphocytes. The neoplastic cells in the metastatic sites also showed exclusive epitheliotropic proliferation in organs, including the trachea, tonsils, esophagus, stomach, small intestine, colon, anal mucosa, liver, pancreas, kidneys, urinary bladder, prostate gland, ear canals, and auricular and ventral skin. Immunohistochemically, the neoplastic cells were positive for CD3 and negative for CD20 as well as CD79α, supporting a diagnosis of CETL with systemic dissemination. In canine CETL with systemic signs, systemic metastasis should be considered even without evident mass formation. Neoplastic lymphocytes of CETL showed distinct epitheliotropism even in the systemic metastatic sites.
authors.affiliation: Laboratory of Veterinary Pathology (Mineshige, Yauchi, Sugahara, Kamiie, Shirota), Azabu University, Kanagawa, JapanVeterinary Teaching Hospital (Kawarai), Azabu University, Kanagawa, JapanLaboratory of Veterinary Internal Medicine II (Segawa, Neo, Hisasue), Azabu University, Kanagawa, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Mineshige
authors.affiliation: Laboratory of Veterinary Pathology (Mineshige, Yauchi, Sugahara, Kamiie, Shirota), Azabu University, Kanagawa, JapanVeterinary Teaching Hospital (Kawarai), Azabu University, Kanagawa, JapanLaboratory of Veterinary Internal Medicine II (Segawa, Neo, Hisasue), Azabu University, Kanagawa, Japan.
authors.forename: Shinpei
authors.initials: S
authors.lastname: Kawarai
authors.affiliation: Laboratory of Veterinary Pathology (Mineshige, Yauchi, Sugahara, Kamiie, Shirota), Azabu University, Kanagawa, JapanVeterinary Teaching Hospital (Kawarai), Azabu University, Kanagawa, JapanLaboratory of Veterinary Internal Medicine II (Segawa, Neo, Hisasue), Azabu University, Kanagawa, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yauchi
authors.affiliation: Laboratory of Veterinary Pathology (Mineshige, Yauchi, Sugahara, Kamiie, Shirota), Azabu University, Kanagawa, JapanVeterinary Teaching Hospital (Kawarai), Azabu University, Kanagawa, JapanLaboratory of Veterinary Internal Medicine II (Segawa, Neo, Hisasue), Azabu University, Kanagawa, Japan.
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Segawa
authors.affiliation: Laboratory of Veterinary Pathology (Mineshige, Yauchi, Sugahara, Kamiie, Shirota), Azabu University, Kanagawa, JapanVeterinary Teaching Hospital (Kawarai), Azabu University, Kanagawa, JapanLaboratory of Veterinary Internal Medicine II (Segawa, Neo, Hisasue), Azabu University, Kanagawa, Japan.
authors.forename: Sakurako
authors.initials: S
authors.lastname: Neo
authors.affiliation: Laboratory of Veterinary Pathology (Mineshige, Yauchi, Sugahara, Kamiie, Shirota), Azabu University, Kanagawa, JapanVeterinary Teaching Hospital (Kawarai), Azabu University, Kanagawa, JapanLaboratory of Veterinary Internal Medicine II (Segawa, Neo, Hisasue), Azabu University, Kanagawa, Japan.
authors.forename: Go
authors.initials: G
authors.lastname: Sugahara
authors.affiliation: Laboratory of Veterinary Pathology (Mineshige, Yauchi, Sugahara, Kamiie, Shirota), Azabu University, Kanagawa, JapanVeterinary Teaching Hospital (Kawarai), Azabu University, Kanagawa, JapanLaboratory of Veterinary Internal Medicine II (Segawa, Neo, Hisasue), Azabu University, Kanagawa, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Kamiie
authors.affiliation: Laboratory of Veterinary Pathology (Mineshige, Yauchi, Sugahara, Kamiie, Shirota), Azabu University, Kanagawa, JapanVeterinary Teaching Hospital (Kawarai), Azabu University, Kanagawa, JapanLaboratory of Veterinary Internal Medicine II (Segawa, Neo, Hisasue), Azabu University, Kanagawa, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Hisasue
authors.affiliation: Laboratory of Veterinary Pathology (Mineshige, Yauchi, Sugahara, Kamiie, Shirota), Azabu University, Kanagawa, JapanVeterinary Teaching Hospital (Kawarai), Azabu University, Kanagawa, JapanLaboratory of Veterinary Internal Medicine II (Segawa, Neo, Hisasue), Azabu University, Kanagawa, Japan shirota@azabu-u.ac.jp.
authors.forename: Kinji
authors.initials: K
authors.lastname: Shirota
mesh_terms: D000818:Animals; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000175:diagnosis* / Q000473:pathology; D004285:Dogs; D017809:Fatal Outcome; D016410:Lymphoma, T-Cell, Cutaneous / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D008297:Male; D009362:Neoplasm Metastasis; D012878:Skin Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*
keywords: Canine; cutaneous epitheliotropic T-cell lymphoma; epitheliotropism; lymphoma