A case of leukaemia cutis in a dog with T-cell chronic lymphocytic leukaemia.

Leukaemia cutis (LC) is the infiltration of neoplastic leukocytes into the skin, characterised by haemorrhagic papules, nodules, and plaques. LC has been reported in human leukaemia patients, but it is extremely rare in dogs. A 13-year-old spayed female Golden Retriever that was previously diagnosed with chronic lymphocytic leukaemia was managed with chlorambucil (20 mg/m2 orally, every 2 weeks) and prednisolone (2 mg/kg orally, every other day) for 8 months; however, immunosuppression was temporarily discontinued because of a bacterial urinary tract infection. Cutaneous signs, including multifocal ecchymosis and white plaques, appeared 1 month after cessation of chemotherapy. Histopathological examination revealed small- to intermediate-sized lymphocytes with mild atypia in a perivascular to interstitial pattern within the superficial dermis. The bands of atypical cells within the superficial dermis were strongly and extensively positive for CD3 on immunohistochemistry. Polymerase chain reaction analysis of the biopsied skin revealed clonal rearrangement of the T-cell receptor gamma locus gene. Given the evidence of clinical signs, peripheral immunophenotyping, histopathology, immunohistochemistry, and clonal gene arrangement, LC was diagnosed. The lesions disappeared when chemotherapy was restarted but were occasionally observed when chemotherapy was stopped. To the authors' best knowledge, this is the first case report of LC in a dog.

Multicentric T-cell lymphoma accompa- nied by infiltration of the peripheral and central nervous system in a fattening pig.

Multicentric lymphomas, usually of B-cell origin, are rather common neoplasms in pigs, which usually affect lymph nodes and different organ systems. An uncommon manifestation of malignant lymphoma represents neoplastic peripheral nerve involvement, which has been reported in human medicine. So far, only single cases of lymphoma with manifestation in peripheral nerves (known as neurolymphomatosis) without leukemic conversion have been mentioned in different animal species others than swine. The present case report describes the occurrence of a multicentric T-cell lymphoma in a fattening pig with marked leukocytosis. The pig was presented with symptoms of lethargy, weight loss, and fever. Bone marrow aspirate contained all stages of granulocytic and erythrocytic precursors, and a remarkable large number of eosinophiles and undifferentiated blasts. At necropsy, the carcass showed generalized lymphadenopathy and severe hepatosplenomegaly. Histological findings included neoplastic round cell infiltrations in lymph nodes, bone marrow, tonsils, lung, spleen, liver, kidneys, urinary bladder, small and large intestine, and meninges. Additionally, neoplastic cells were present in the sciatic and medial plantar nerve of the left hind leg. The diagnosis T-cell lymphoma was confirmed immunohistochemically. To the author's knowledge, this work represents the first report of peripheral nerve involvement in a pig with multicentric T-cell lymphoma accompanied by CNS involvement and leukemia.

Acute respiratory failure caused by leukaemic infiltration of the lung of a dog.

A seven-year-old crossbred male dog with a suspected leukaemic condition was referred for investigation and treatment. A bone marrow aspirate revealed an acute myeloid leukaemia. Combination chemotherapy was administered and the dog initially improved, but 18 days after the initiation of therapy its body condition deteriorated and the animal developed acute respiratory distress. On postmortem examination, extensive leukaemic pulmonary infiltrates were evident.

Computed tomography and magnetic resonance findings in two dogs and a cat with intracranial lesions.

Two dogs and a cat with intracranial lesions were evaluated by both computed tomography (CT) and magnetic resonance (MR) imaging. In a dog with vestibular syndrome, better quality images of the medulla oblongata surrounded by thick bones were obtained by MR than by CT, on which the appearance of artifacts impeded the clear image of the area. In a dog with multiple brain metastases of lymphoma, contrast CT delineated lesions more clearly than MR, which was performed one week after CT. During that week dexamethasone which might affect the clarity of MR images of the lesion was administered to reduce brain edema. In a cat with meningeal syndrome of lymphocytic leukemia, only contrast MR imaging identified the width and site of the lesion. These results indicate that it is necessary to select either one of these imaging methods according to the type and site of lesions that are suspected in a particular case.