Draining tracts and nodules in dogs and cats

Draining tracts and nodules in the dog and cat can present a diagnostic challenge to the veterinarian. A systematic approach and a complete list of differential diagnoses are needed to define the underlying disease, so that appropriate therapeutic management can be instituted and prognosis can be discussed with the owner. The purpose of this article is to review a complete list of differential diagnoses for draining tracts and nodules in the dog and cat, and discuss the appropriate diagnostic steps including cytology, biopsy and histopathology, culture and sensitivity, serology, and diagnostic imaging that are an important part of the work-up for draining tracts and nodules.