Severe respiratory distress caused by multicentric small lymphocytic B‐cell lymphoma in a Lacaune sheep

Abstract A 6‐year‐old Lacaune ewe from an experimental dairy flock presented with severe respiratory distress, reduced milk production, and mammary nodules. Clinical examination revealed bilateral inspiratory dyspnoea, mucous nasal discharge, a productive cough, and generalised lymphadenomegaly. Although chronic proliferative rhinitis was initially suspected, anti‐inflammatory and antibiotic treatment provided only temporary relief. The ewe's condition subsequently deteriorated, culminating in death. Tumour‐like masses were detected and confirmed in the nasal cavity, lungs and lymph nodes. Histopathological and immunohistochemical analyses established a diagnosis of B‐cell multicentric lymphoma concurrent with ovine pulmonary adenocarcinoma. This case highlights the importance of including rare neoplastic conditions in the differential diagnosis of respiratory and systemic clinical signs in sheep, and emphasises the diagnostic challenges posed by their resemblance to more common diseases.