Rhabdomyosarcoma of the Maxillary Gingiva

Background: Rhabdomyosarcoma is a malignant neoplasm of primitive mesenchyme exhibiting skeletal muscle differentiation. Oral rhabdomyosarcoma is rare and accounts for only 0.04% of all head and neck malignancies. Methods: A 33‐year‐old woman presented with an erythematous gingival mass involving the anterior maxillary gingiva. The lesion had been present for ≥13 months before presentation, and in recent months, it had become intermittently painful. Results: Clinical examination exhibited erythema and enlargement of the interdental papillae between the left maxillary canine, lateral incisor, and central incisor. The tissue was boggy and tender on palpation. Incisional biopsies were performed, and microscopic examination showed a cellular proliferation of spindle‐shaped to ovoid cells with hyperchromatic, enlarged, and pleomorphic nuclei. Many of the tumor cells exhibited abundant eosinophilic cytoplasm. Immunohistochemical stains showed the tumor cells to be positive for desmin, myogenin, and myogenic differentiation 1 (MyoD1). A diagnosis of embryonal rhabdomyosarcoma was made. The patient was treated by surgical resection with postoperative chemotherapy and radiation. The patient had no evidence of disease at a follow‐up examination 1 month after completion of therapy. Conclusions: Oral rhabdomyosarcoma can develop insidiously. Pain is a variable presenting symptom, and early lesions may be mistaken for benign neoplastic, inflammatory, or infectious processes. Over several decades, a multidisciplinary treatment approach that includes surgical removal if resectable, in combination with multiagent chemotherapy and possibly radiation therapy, has improved survival rates.