The Face of an Aggressive Tumor: A Rare Case of Sinonasal-Alveolar Rhabdomyosarcoma in Adolescence

Abstract

Alveolar Rhabdomyosarcoma (ARMS) is an uncommon and aggressive subtype of Rhabdomyosarcoma (RMS) associated with a poor prognosis, with a 5-year survival rate as low as 28.9%. In adolescents aged 15–19 years, the incidence is approximately 1.4%, most frequently involving the extremities, with a high propensity for distant metastasis. Sinonasal involvement is exceedingly rare. We describe a 16-year-old male who presented with a progressively enlarging mass over the right nasal and maxillofacial region, extending to the orbit, accompanied by recurrent epistaxis, reduced smell, and visual impairment. Examination revealed a solid mass occupying the nasal cavity, right maxilla, and inferior orbit, with right-sided proptosis and submandibular and cervical lymphadenopathy. Nasopharyngeal CT scan demonstrated a solid mass with nasal septum destruction. Six months later, the lesion extended into the maxillary and ethmoid sinuses and orbital wall. Macroscopically, the tumor measured approximately 5 cc, was whitish-brown, and firm. Microscopically, it showed predominantly solid and trabecular patterns with focal alveolar arrangement, pleomorphic cells, and hyperchromatic nuclei. The initial diagnosis favored ARMS with a differential diagnosis of Keratinizing Squamous Cell Carcinoma; immunohistochemistry confirmed ARMS. The patient underwent 13 cycles of chemotherapy and 42 fractions of radiotherapy. Despite initial response, local recurrence developed, and the patient died within three years of diagnosis. ARMS is an aggressive RMS subtype with poor prognosis, often presenting with early metastasis. This case highlights an unusual primary site in the nasal cavity with rapid local invasion to adjacent structures, contrasting with the usual extremity involvement. Diagnosis required combined histopathological and immunohistochemical evaluation, showing Desmin and Myogenin positivity consistent with ARMS. Despite multimodal therapy, early recurrence and poor survival emphasize the need for prompt recognition, accurate diagnosis, and exploration of improved therapeutic strategies.