Cytopathological diagnostic in canine lymphoma

Abstract

Lymphomas are tumors that may be frequently diagnosed in dogs. The main suspicion for this neoplasic disease arises when lymphnodes become enlarged without the existence of any obvious antigenic stimulation. Fine needle aspiration from enlarged lymphnodes with the preparation of cytological slides allows for an early and relatively precise diagnostic in lymphoma cases. We used this technique, along with the May Grunwald Giemsa staining method to search for cytological and nuclear abnormalities that might indicate the evolution of a lymphoma in dogs that presented with enlarged lymphnodes. We found a constant mixture of medium sized and large lymphocytes, multinucleated cells, anisokaryosis, various nuclear shapes (multiple indentations), multiple visible nucleoli, variable cytoplasmic/nuclear ratios and cytoplasmatic chromatic properties (basophilia, light basophilia). Also, the mitotic index measured per 5 HPF fields (x400) was sometimes a strong indicative of malignancy. All of the cases diagnosed with lymphoma based on cytopathological examination were later confirmed through histopathological examination. This suggests that this simple and fast technique that is applicable also in small animal practices may be used to diagnose lymphomas in dogs with a relative high accuracy.