Cutaneous, multilocular T-cell lymphosarcoma in a horse--clinical, ultrasonographic and pathological findings.

Clinical, ultrasonographic and pathological findings of a cutaneous, multilocular T-cell lymphosarcoma (malignant lymphoma) in a 13-year-old, brown Austrian warmblood mare are reported. The horse was under clinical observation, and the tumours were sonographically monitored over an 8 month period, revealing worsening of body condition, weight loss, lameness of the left hindlimb and a slight increase in the tumours size. Most of the tumours were covered by normal skin, one showed ulceration. Ultrasonography of the tumours allowed accurate anatomical localization in relation to the adjoining tissue, assessment of their internal structure, of involvement of adjacent muscles and of a regional lymph node, and it facilitated the percutaneous fine-needle aspiration. Necropsy confirmed muscular infiltration in three locations. Light microscopy and immunohistology led to the diagnosis of a T-cell lymphosarcoma.