An Atypical Presentation of Sinonasal Tract Alveolar Rhabdomyosarcoma in a Young Male Patient Submitted to Multimodality Treatment.

Rhabdomyosarcoma (RMS), a malignant tumor derived from the neoplastic proliferation of striated skeletal muscle cells, is the most common pediatric soft tissue sarcoma. Its treatment is mainly based on neoadjuvant chemotherapy (QT+), surgical resection, and adjuvant radiotherapy (RT+). RT+ has shown satisfactory results for locoregional control of the disease, in spite of promoting local side effects. The present case report was aimed at describing the clinical and therapeutic characteristics and the management of complications resulting from multimodal therapy in a patient with an atypical presentation of RMS in the sinonasal tract. A 20-year-old Afro-descendant man complained of an expansive tumor lesion, with left eye proptosis that reduced visual acuity and caused severe regional pain. Imaging analysis showed an extensive and infiltrative lesion in the periorbital region, sinonasal tract, left maxilla, and orbital roof. According to the histopathological analysis, the diagnosis was established corresponding to parameningeal alveolar RMS that was unresectable. Treatment was initiated with three cycles of QT+ which showed partial response and later RT+. After completing half of the RT+ sessions, the patient showed a complete response with reduction in tumor volume and improvement in pain and local conditions. Side effects such as alopecia and dermatological changes induced by radiation were observed. Moreover, painful erythematous areas were observed in the region of the hard and soft palate, uvula, and oropharynx, compatible with Grade 2 mucositis lesions. After the cytological swab test, some of them were diagnosed as herpes simplex lesions; thickening and decrease in salivary flow were also found. A local drug therapy approach was instituted, and photobiomodulation was performed to manage oral complications. RT+ was shown to be effective in locoregional control of the disease; however, the early management of its undesirable effects on the surrounding tissues was required.