Inflammatory Mammary Carcinoma in a Captive Bengal Tiger (Panthera tigris tigris) with Lymph Node and Pulmonary Metastases.

Inflammatory mammary carcinoma (IMC) is an aggressive mammary carcinoma phenotype characterized by tumor emboli within superficial dermal lymphatic vessels and early metastasis. A captive Bengal tiger (Panthera tigris tigris) presented with large abdominal mammary masses and regional lymphadenopathy; contrast-enhanced computed tomography also revealed a pulmonary nodule. Postmortem examination and histopathology confirmed mammary carcinoma with dermal lymphatic tumor emboli and metastases to regional lymph nodes and the lung. Tumor emboli were cytokeratin positive, supporting epithelial origin and an IMC diagnosis, and neoplastic cells were immunopositive for cytokeratin with concurrent vimentin immunoreactivity. This case highlights the clinicopathologic basis of IMC and the diagnostic importance of including full-thickness skin and adjacent subcutis in the sampling plan.