Outcomes and prognostic factors in canine epitheliotropic and nonepitheliotropic cutaneous T-cell lymphomas.

Canine cutaneous lymphoma is an uncommon lymphoma in dogs. Most canine cutaneous lymphoma cases have a T-cell origin. Canine cutaneous T-cell lymphoma (CTCL) is classified into epitheliotropic and nonepitheliotropic cutaneous lymphomas, and each type of lymphoma is subclassified into several histological subtypes. Limited information is available regarding the prognostic significance of clinical variables and histopathological subtypes in dogs with CTCL. This retrospective study aimed to investigate the influence of clinical variables and histopathological subtypes on the prognosis of dogs with CTCL. Forty-six dogs diagnosed with CTCL by histopathological examination were included. Histopathological specimens were reexamined and classified into CTCL subtypes. The influence of the type of skin lesion, histopathological subtype, haematological examination results and treatment response on the overall survival time (OS) was examined. Thirty-one dogs were diagnosed with epitheliotropic CTCL (mycosis fungoides in 28 dogs; pagetoid reticulosis in 3 dogs) and 15 dogs were diagnosed with nonepitheliotropic CTCL (anaplastic large T-cell lymphoma in 6 dogs; peripheral T-cell lymphoma, not otherwise specified, in 9 dogs). The OS of dogs diagnosed with epitheliotropic CTCL (141 days) was significantly shorter than that of dogs diagnosed with nonepitheliotropic CTCL (374 days). As clinical variables, the presence of neoplastic lymphocytes in peripheral blood, thrombocytopenia and initial chemotherapeutic response was related to prognosis. Our results demonstrated that histopathological subtype and several clinical variables were found to influence the prognosis of dogs with CTCL.

Iridociliary adenocarcinoma with oncocytic change in a dog.

An intraocular mass lesion was found in the left eyeball in a spayed female Pembroke Welsh Corgi dog. The surgically resected left eyeball was pathologically examined. Histologically, the mass lesion consisted of proliferation of the atypical cuboidal or columnar epithelial cells, arranging in papillary, tubular or solid form. In addition, some neoplastic cells showed oncocytic change characterized as large oval cells with numerous eosinophilic intracytoplasmic granules. Cytoplasm of the oncocytic cells showed dark blue granules by phosphotungstic acid-hematoxylin stain. Immunohistochemically, the oncocytic cells were intensely positive for cytochrome C. Based on these findings, the ocular mass was diagnosed as iridociliary adenocarcinoma with oncocytic change. The findings indicate that the oncocytic changes of the neoplastic epithelial cells might be caused by mitochondrial accumulation.

Primary ischial osteosarcoma occupying the pelvic cavity in a Japanese Black cow.

A 10-year-old Japanese Black cow presented with a swelling of the right femur, and a hard, large mass occupied the pelvic cavity. The mass strongly adhered to the visceral surface of the ischium and had posteriorly invaded among the right femoral muscles. Histologically, the mass was composed of neoplastic osteoblasts and exhibited osteoid and immature trabecular bone production. In the region where the mass adhered to the ischium, neoplastic cells were continuously proliferating into the medullary cavity. Tumor emboli were observed in the small vessels of the femoral muscles and lungs. Based on these findings, the mass was diagnosed as an osteosarcoma and considered to have arisen from the ischium.