Cytologic diagnosis of Mycoplasma in a recurrent abscess from a cat.

A 10-year-old, neutered male, indoor/outdoor domestic shorthair cat was presented for a mass on the right front paw. The mass was treated as an abscess, and despite initial resolution, the mass recurred and ruptured approximately 1 month later. This mass successfully resolved with intense management as an open wound. Several days later, the cat developed vomiting and inappetence, and a new mass was noted on the lateral aspect of the right rear limb. Aspirates from the new mass were submitted for cytologic evaluation and bacterial cultures. Anaerobic and aerobic bacterial cultures were negative. Cytologic evaluation revealed septic neutrophilic inflammation with small rod, cocci, curved, and ring forms of bacteria seen, and Mycoplasma spp. infection was suspected based on the morphology of the bacteria. Polymerase chain reaction followed by gene sequencing revealed 86% similarity for Mycoplasma elephantis. The cat was treated with a fluoroquinolone antibiotic and clinically improved, with resolution of the abscess. This case highlights the importance of recognizing the morphologic appearance of Mycoplasma spp. on cytologic examination to help guide additional testing choices and therapeutic planning.