Can you discover the cause?
This two-year-old spayed female cat was presented for evaluation of a large (4- x 4.5- x 5.4-cm) tail mass. On palpation, the mass felt turgid and hot, appeared to be causing pain, and had serosanguineous discharge (see photo above). Radiographs revealed a large soft tissue swelling with lysis of caudal coccygeal vertebral bodies (see photo below).
An excisional biopsy, which was palliative, provided a large sample for histopathologic examination. Representative immunohistochemistry fields from the sample are shown below.
What's your diagnosis?
From exam room tips to practice management insights, get trusted veterinary news delivered straight to your inbox—subscribe to dvm360.