A Rare Case of a Concurrent Mandibular Odontogenic Keratocyst and Oral Rhabdomyosarcoma in a Young Cat.

A 3-year-old neutered male domestic shorthair cat was presented with acute pain during feeding and with hypersalivation, without any history of trauma. Oral examination revealed a lateral deviation of the left mandible and a soft, painful swelling at the site of the missing left mandibular canine tooth (304). Intraoral radiographs and computed tomography (CT) demonstrated extensive bone lysis of the left mandible and a cystic lesion extending from the mandibular symphysis to the level of the mandibular fourth premolar tooth (308), within which the embedded canine tooth was located. Regional lymph nodes appeared normal on clinical and CT examination, and fine-needle aspiration of the left mandibular node showed reactive changes. A left-sided segmental mandibulectomy, from the mandibular symphysis to the mandibular first molar tooth (309), was performed to remove the cyst and the affected bone. Histopathological evaluation identified features consistent with an odontogenic keratocyst and concurrently confirmed the presence of a rhabdomyosarcoma. Three months after surgery, the cat was presented with a rapidly enlarging mass firmly attached to the soft tissues of the mandibulectomy site and it was euthanized a few days later. This case represents the first reported coexistence of an odontogenic keratocyst with a malignant neoplasm, specifically rhabdomyosarcoma, in a cat. The findings highlight the importance of thorough investigation of cystic oral lesions, as they may be associated with severe bone destruction and concurrent malignancy, even in young animals.