Dermal chondrosarcoma in a cat with prolonged survival after limb amputation.

A 5-year-old male entire domestic shorthair cat presented with a firm dermal mass on the dorsal left metatarsal region. Diagnostic investigations included haematology, biochemistry, urinalysis, biopsy, histopathology and computed tomography staging. Histopathology of the tissue biopsy, including immunohistochemistry, confirmed a dermal chondrosarcoma (CSA), and computed tomography supported an extraskeletal origin. Pretreatment staging did not identify metastatic disease. Curative-intent limb amputation was therefore performed, resulting in tumour-free surgical margins. No adjuvant treatment was used. The cat underwent regular reevaluation for 3 years and remained free of local recurrence or metastatic disease. Dermal CSA is rarely reported in cats, and information regarding biological behaviour and outcome is limited. This patient experienced long-term control, demonstrating that with complete surgical excision alone, extraskeletal CSAs can have a favourable outcome.