An atypical case of lymphosarcoma (sporadic bovine leukosis) in a heifer.

An 18-month-old Friesian heifer had several unusual, raised, black, cutaneous plaques, some of which were up to 20 cm in diameter, on its head and neck, limbs, thorax and perineum. There was also generalised lymphadenopathy. A clinical diagnosis of lymphosarcoma (sporadic bovine leukosis) was derived from a fine needle aspiration of a skin lesion. Post mortem and histological examinations confirmed a multicentric lymphosarcoma with widespread infiltration into many of the tissues recognised as predilection sites for this type of tumour. However, in the authors' experience, the presence of tumour masses in the trachea and the right mainstem bronchus was atypical.