A 2-year-old female llama (Lama glama) from a private zoological park was submitted to the Pathology Department of the Faculty of Veterinary Medicine from Cluj-Napoca (Romania) for necropsy. The animal had a history of depression, anorexia, progressive weakening, ataxia, decubitus ulcers, fever, dyspnea, and abdominal distension. Death occurred 6 weeks after the onset of clinical signs. Necropsy, and cytological, histological, and immunohistochemical examinations were performed. Grossly, the animal was emaciated. Subcutaneous edema of the posterior limbs, abdomen, and thorax, hydrothorax, hydro-pericardium, and severe ascites (approximately 15 liters of fluid) with fibrin clots adherent to the visceral peritoneum, and multiple, acute, gastric ulcers were observed.A firm, white-gray, multinodular mass, 25 cm in diameter was found in the liver parenchyma. Moreover, multiple small nodules, unencapsulated, with poorly defined margins, and ranging from 0.5 to 4 cm in diameter scattered throughout the liver parenchyma were present. The cut surface of the tumors varied from gray-white to red-brown (Fig. 1). Multiple areas of necrosis, a few microabscesses, and venous thrombosis were also found within the liver parenchyma. Similar nodular lesions affecting the mesenteric, tracheobronchial, and submandibular lymph nodes, lungs (Fig. 2), parietal pleura, pericardium, diaphragm, the serosal surface of the gut, and peritoneum were present. Lesions were umbelicated, firm, and gray, and ranged from 0.5 to 3 cm in diameter. The lymph nodes were markedly enlarged and multifocally replaced by metastatic lesions. No tumors were detected in other organs, including kidney, stomach, pancreas, and mammary glands.Samples from liver, lung, lymph nodes, diaphragm, and pericardium were evaluated by cytological, histological, and immunohistochemical examinations. For cytology, multiple smears from the hepatic masses were stained by Dia-Quick Panoptic.a For histology, the samples were fixed in 10% phosphate buffered formalin for 24 hr, embedded in paraffin wax, cut into 3-5 µm sections, and stained with hematoxylin and eosin and periodic acid-Schiff (PAS). Histological interpretation of lesions was done according to the World Health Organization Classification of Tumors of the Alimentary System of Domestic Animals.6 For immunohistochemistry, sections from liver mass, lung nodules, and normal liver and lung tissue (inner control) were selected. After dewaxing, heat-induced epitope retrieval pretreatment, and endogenous peroxidase inactivation (H 2 O 2 1% in phosphate buffered saline b [PBS]), slides were incubated with goat serum 10% in PBS for reducing background staining. Sections were incubated with the following mouse monoclonal primary antibodies: broad spectrum cytokeratins (panCK), c CK20, c CK19, c CK7, c thyroid transcription factor 1 (TTF1), c and carcinoembryonic antigen (CEA), b for 24 hr at 4°C. After washes, the secondary antibody (labeled streptavidin biotin) was applied, followed by incubation with diaminobenzidine. Negative...