EPITHELIOID RHABDOMYOSARCOMA OF THE ORAL CAVITY, NOVEL LOCATION OF A RARE ENTITY: A CASE REPORT

Abstract

Background Rhabdomyosarcoma, a malignant neoplasm, is characterized by skeletal muscle differentiation. Only 33 cases of the epithelioid variant have been reported, and just 8 of them were located in the head and neck region. This aggressive entity usually presents as a fast-growing, asymptomatic infiltrative mass and presents predominantly in adults. A 53-year-old male, who was edentulous and a former smoker, presented with enlargement of 2 months’ duration in the right maxillary vestibule. A clinically palpable mass was noted under the mucosa. No adenopathy or cranial nerves deficit was observed on physical examination. The initial panoramic radiograph showed a corticated radiolucent entity located on the right maxilla, with extension into the right maxillary sinus. Multidetector computed tomography (MDCT) and positron emission tomography/computed tomography (PET/CT) were performed. CT revealed an enhancing soft tissue mass of the right alveolar ridge with extension to the maxillary sinus, with erosion of the anterior and lateral walls of the sinus and the adjacent alveolar ridge. PET/CT showed a right maxillary fluorodeoxyglucose (FDG) high uptake and right neck level IIA lymph nodes with mild uptake. An incisional biopsy was performed. The histologic appearance and immunohistochemical profile supported a diagnosis of high-grade epithelioid rhabdomyosarcoma. The treatment protocol was right maxillectomy and right neck dissection with coadjuvant radiation therapy. After 1.5 years, follow-up CT was performed and did not show any signs of recurrence or metastatic disease. Discussion/Conclusions Epithelioid rhabdomyosarcoma is a rare variant of rhabdomyosarcoma. To the best of our knowledge, none has been reported in the oral cavity region; thus, this is the first case of this aggressive variant described in this location. This entity may develop without any apparent symptoms or signs of a malignant entity, thus mimicking the appearance of a benign neoplasm or inflammatory process. A comprehensive multidisciplinary approach is advised to diagnose and treat this entity accordingly.