Osteomyelitis and fracture callus abscessation secondary to a foreign body reaction in a traumatic open fracture of the zygomatic bone of a puppy

A five-month-old male labrador retriever presented with a large (6×3×5 cm) firm swelling associated with the right zygomatic arch. The dog suffered a bite wound two months previously, causing puncture wounds dorsal to the orbit where radiographs demonstrated a minimally displaced fracture of the zygomatic arch and surrounding soft, fluctuant swelling. Following three to four weeks of conservative management, the swelling had partially ossified. CT of the skull demonstrated a large cavitary osseous lesion of the right zygomatic arch associated with the previous fracture site. A lateral approach was used to perform marginal excision of the mass, preserving the eye. Histopathology of the mass revealed woven bone formation, granulation tissue lining the cavity and a fragment of plant material within the cavity. The recovery from surgery was unremarkable, and the dog did not suffer any intraoperative or postoperative complications. The dog was clinically normal at follow-up 21 months post surgery.