P2.218: From Toothache to Tumor: Facial Swelling as the First Sign of Alveolar Rhabdomyosarcoma

Introduction: Facial swelling is a common presentation in pediatric patients with a broad differential, ranging from infections to neoplasms. While most cases are benign and respond to routine treatment, persistent swelling despite appropriate management warrants further evaluation for serious underlying causes. Rhabdomyosarcoma (RMS), the most common soft tissue sarcoma in children, often involves the head and neck region. However, primary RMS of the jaw, particularly the alveolar subtype, is exceedingly rare and typically follows a more aggressive course. We present a case of a previously healthy 4-year-old male with persistent right-sided facial swelling ultimately diagnosed as alveolar RMS of the maxilla.

Case Description: A 4-year-old male with no significant past medical history presented with one month of progressive right-sided facial swelling. Symptoms began with jaw discomfort, initially treated with multiple antibiotics for presumed dental abscess. A subsequent tooth extraction failed to improve the swelling. On admission, vital signs revealed mild tachycardia. He appeared well, but physical examination showed a firm, non-tender, non-mobile facial mass on the right, extending from the gingivobuccal sulcus to the mandible, with associated trismus.
Laboratory results, including CBC, CMP, and inflammatory markers, were within normal limits. CT of the neck revealed a large contrast-enhancing mass with destruction of the right mandibular ramus and body. He was admitted for further evaluation by hematology/oncology, ENT, dental, and pediatric surgery teams. Image-guided biopsy demonstrated a small round blue cell tumor consistent with alveolar RMS. FISH testing for FOXO1 rearrangement was negative. Staging workup including chest X-ray, chest CT, and brain/neck MRI showed no metastasis. He was classified as intermediate-risk and started on Children’s Oncology Group protocol D9803 with vincristine, dactinomycin, and cyclophosphamide (VAC) versus VAC plus topotecan.

Discussion: Facial swelling in children is typically due to infections or trauma. However, persistence despite treatment, especially with signs such as trismus or bony destruction, should raise concern for malignancy. In this case, imaging and poor clinical response highlighted the need for further investigation. RMS, although rare, should be included in the differential, especially in pediatric head and neck masses. Early identification and multidisciplinary involvement were critical in achieving a timely diagnosis and initiating therapy.

Conclusion: This case underscores the importance of considering malignancy in children with facial swelling unresponsive to standard interventions. Thorough evaluation and a broad differential are essential for early diagnosis and appropriate treatment of rare but serious conditions like alveolar rhabdomyosarcoma.