Gammopathies associated with plasma cell neoplasms in a 15-year-old female spayed domestic shorthaired cat and a 9-year-old female spayed Rottweiler dog were evaluated by serum protein electrophoresis. In the cat, the plasma cell neoplasm was found in the liver and spleen, and an evaluable sample of bone marrow was not obtained. Some of the plasma cells had the morphologic appearance of flame cells. The paraprotein was confirmed as IgG based on agar gel immunodiffusion precipitation and both immunocytochemical and immunohistochemical staining. The dog had multiple myeloma with production of IgG and IgA paraproteins. In both cases, serum proteins were evaluated by 2 methods of protein electrophoresis: cellulose acetate electrophoresis (CAE) and capillary zone electrophoresis (CZE). In the cat and the dog, CAE showed a single large oligoclonal-like peak, which occurred in the γ-region in the cat and the β-γ-region in the dog, whereas CZE showed a biclonal gammopathy with 2 very close narrow spikes in the γ- and β-γ-regions in the cat and dog, respectively. In selected cases, CZE may be more effective than routine CAE in distinguishing oligoclonal from monoclonal or biclonal paraproteinemia.

An eight‐year‐old female German wirehaired pointer was presented with signs of respiratory distress. Clinical examination, laboratory results, thoracic radiography and echocardiography indicated the presence of a diffuse interstitial lung disease with secondary appropriate erythrocytosis, pulmonary hypertension and cor pulmonale. Transthoracic fine needle aspiration biopsy of the lung suggested malignant epithelial neoplasia. A primary lung cancer with an unusually diffuse distribution of miliary/micronodular lesions was found at postmortem examination. Histological diagnosis was bronchiolo‐alveolar carcinoma. Bronchiolo‐alveolar carcinoma can occasionally occur in a diffuse fashion involving most or all of the lung parenchyma. In man, diffuse bronchiolo‐alveolar carcinoma is considered a great imitator of other, more common diffuse interstitial forms of lung disease. This case report indicates that it is also a differential diagnosis to consider in dogs.

A 3-year-old female mixed-breed dog was referred with a 2-day history of serious dyspnea, coughing, lethargy, anorexia, and a low-grade right anterior lameness. At presentation, the dog had an increased respiratory rate, dull heart and lung sounds, and cyanotic mucous membranes. It was hyperthermic and slightly dehydrated. Laboratory findings showed mild neutrophilia with a left shift, while serum biochemistry variables were in the normal range. However, urinalysis revealed mild proteinuria and rare erythrocytes and leukocytes on sediment examination. Thoracic radiographs showed a diffuse mixed interstitial and alveolar pattern with an air bronchogram, while appendicular radiographs showed a right humeral interrupted brush-like periosteal reaction. Thoracic ultrasonography revealed mediastinal lymph node enlargement. Cytology from a fine-needle aspirate of mediastinal lymph nodes revealed a pyogranulomatous lymphadenitis with numerous fungal hyphae. Culture on Sabouraud dextrose agar isolated dark fungal colonies with microscopic features consistent with Cladosporium spp. Sequencing of the internal transcribed spacer region identified the fungus as a species of the Cladosporium cladosporioides-complex.

An eight-year-old female German wirehaired pointer was presented with signs of respiratory distress. Clinical examination, laboratory results, thoracic radiography and echocardiography indicated the presence of a diffuse interstitial lung disease with secondary appropriate erythrocytosis, pulmonary hypertension and cor pulmonale. Transthoracic fine needle aspiration biopsy of the lung suggested malignant epithelial neoplasia. A primary lung cancer with an unusually diffuse distribution of miliary/micronodular lesions was found at postmortem examination. Histological diagnosis was bronchiolo-alveolar carcinoma. Bronchiolo-alveolar carcinoma can occasionally occur in a diffuse fashion involving most or all of the lung parenchyma. In man, diffuse bronchiolo-alveolar carcinoma is considered a great imitator of other, more common diffuse interstitial forms of lung disease. This case report indicates that it is also a differential diagnosis to consider in dogs.