A Rare Presentation of Alveolar Rhabdomyosarcoma of the Sinonasal and Nasopharyngeal Region With Bone Marrow Metastasis.

We report the case of a Hispanic woman in her 50s who presented to the emergency department with persistent hip and left lower extremity pain, followed by progressive anosmia and a right-sided neck mass. On physical examination, the patient had a palpable lymph node in the right submandibular area, and she reported a history of anosmia. A CT scan of the neck and face revealed an enhancing mass in the superior nasal cavity/ethmoid sinus with cribriform plate dehiscence and pachymeningeal enhancement and a right cervical lymph node. A biopsy of the lymph node revealed alveolar rhabdomyosarcoma (ARMS) from the sinonasal and nasopharyngeal region. Further studies revealed bone marrow metastatic disease. The patient started chemotherapy with vincristine, doxorubicin, and ifosfamide. Rhabdomyosarcoma is the most common soft tissue sarcoma in the pediatric population, but it is rare in adults. Moreover, the ARMS subtype, which is also found in the nasal cavities, is even less common in adults. Rhabdomyosarcoma is typically seen in the pediatric population as a rare soft tissue tumor, but it is even more uncommon in adults. Current treatment protocols in adult ARMS are extrapolated from pediatric regimens, but adults often experience greater toxicity and have poorer outcomes, highlighting the need for adult-specific clinical trials. This case is a great example of the importance of timely recognition, comprehensive diagnostic workup, and multidisciplinary management approaches for the optimal care of rare adult ARMS.