ABSTRACT
Fine needle aspirates of lesions in the skin and subcutaneous tissues are the most common type of cytologic sample collected from companion animals. Cytology of cutaneous and subcutaneous lesions often provides a fast, accurate analysis of the underlying pathogenesis of disease. This chapter argues that the limitations of cytology are minor for most lesions in the skin and subcutaneous tissues. Cytology preparations may also contain mammary secretions, which usually have low cellularity and may contain lipid or proteinaceous secretory material. The cytologic appearance of aspirates from masses in or under the skin can be grouped into very broad categories: acellular samples, samples containing cellular debris, hemodiluted samples, inflammatory samples, or tissue samples. Mammary masses are an important example of lesions that may be difficult to diagnose cytologically. Small clusters of benign-appearing epithelial cells that line the cyst may be present in the cytologic sample.
