SPINDLE CELL VARIANT OF RHABDOMYOSARCOMA IN THE ORAL CAVITY: A CASE REPORT

Abstract

<h3>Introduction</h3> Rhabdomyosarcoma (RMS) is a malignant mesenchymal tumor derived from skeletal muscle. The head and neck, genitourinary tract, and extremities are the most common sites for RMS. RMS is less frequent in the oral cavity, which accounts for only 0.04% of all malignancies in the head and neck. We report a rare case of the spindle cell variant of RMS arising from the right retromolar region in a 14-year-old boy. <h3>Case Report</h3> A 14-year-old boy presented to the oral surgery department with right facial enlargement that had appeared 7 months earlier with rapid evolution. During extraoral examination, an extensive swelling on the right side of his face was observed with an undefined margin. On intraoral examination, an exophytic, mixed red and white mass was observed at the retromolar region. The mass extended posteriorly with involvement of the posterior lateral aspect of the hard palate. Computed tomography revealed a large expansible lesion occupying the right buccal mucosa infratemporal, zygomatic, and parapharyngeal regions. A facial nerve examination showed weakness at the right marginal mandibular branch and buccal branch. <h3>Discussion</h3> An incisional biopsy was performed. Histopathologic examination showed neoplastic spindle cell proliferation arranged in streaming fascicles with scattered rhabdomyoblasts. Immunohistochemical staining revealed strong positivity for myogenin and desmin. The diagnosis of a spindle cell variant of RMS was made on the basis of the histomorphologic features and immunohistochemistry findings. <h3>Conclusion</h3> Recognition of the accurate diagnosis and histologic subtype of RMS is crucial for the outline of treatment. Early detection is vital for better disease prognosis.