Background <p>The odontogenic keratocyst (OKC) is a benign but locally aggressive cystic lesion known for its erosive potential and high recurrence (5–62%) rate. While parotid involvement is exceptionally rare, the OKC’s bone erosive ability can lead to the formation of a fistula draining extra-orally through the parotid region.</p> Case Presentation <p>A 43-year-old female presented with a 2-week history of painful swelling with draining sinus in the left pre-auricular region. Initial clinical examination and imaging revealed a fistula tract originating from a large, infected cystic lesion in the mandibular ramus that had eroded through the buccal cortex into the parotid gland. The patient was treated with a two-part approach: surgical enucleation of the cystic lesion turning out to be OKC and serial injections of hypertonic saline (3% NaCl) into the fistula tract to induce fibrosis and promote closure.</p> Conclusion <p>This case highlights the importance of considering an odontogenic keratocyst in the differential diagnosis of parotid fistulas, particularly when a bony lesion in the posterior mandible or condyle is present. It also demonstrates hypertonic saline as a cost-effective and minimally invasive adjunct therapy that can effectively manage and close persistent fistulas, thereby reducing the need for more complex and invasive surgical interventions.</p>