Extramedullary Plasmacytoma of the Nasal Cavity, Paranasal Sinuses, and Nasopharynx: Report of Two Cases and Review of Literature.

Extramedullary plasmacytoma (EMP) is a rare plasma cell neoplasm occurring outside the bone marrow, predominantly in the head and neck region. Representing 3%-5% of all plasma cell neoplasms, EMP poses significant diagnostic and therapeutic challenges due to its rarity and,proximity to vital structures. We report two cases of EMP involving the nasal cavity, paranasal sinuses, and nasopharynx. A 30-year-old male presented with right diplopia, headache, and bilateral nasal blockage. Examination revealed a nasopharyngeal mass with bony erosion and multiple osteolytic lesions. Histopathology and immunohistochemistry confirmed plasmacytoma, and systemic involvement was excluded. The patient underwent chemoradiotherapy with satisfactory outcomes. A 27-year-old female presented with nasal bleeding, progressive nasal blockage, facial swelling, snoring, and anosmia. Imaging revealed a mass originating from the left maxillary sinus extending to adjacent structures. Histopathology and immunohistochemistry confirmed plasmacytoma. Systemic workup was negative. The patient was treated with radiotherapy, with a good treatment outcomes. EMP of the nasal cavity, paranasal sinuses, and nasopharynx is rare, particularly in younger patients. Accurate diagnosis and appropriate treatment, often involving radiotherapy, are crucial for favorable outcomes. Awareness and a high index of suspicion are essential for early diagnosis and management.