Oshin A, Griffon D, Lemberger K, Naughton J, Barger A. Department of Small Animal Surgery, Affiliated Veterinary Specialists, 1668 Mallory Lane, Brentwood, Tennessee 37027, USA. JAAHA 2009 Sep-Oct 45 5 239-44 A 4-year-old, spayed female, mixed-breed dog was presented for evaluation of chronic left hind-limb lameness. Lytic lesions were observed in the left patella on radiographs of the stifle. A biopsy of the patella led to a histopathological diagnosis of blastomycosis. Surgical debridement followed by a 90-day course of itraconazole and physical rehabilitation resolved the clinical signs and stopped the progression of radiographic lesions. Blastomycosis should be considered as a differential diagnosis for stifle joint lameness with lytic lesions in the patella.