BACKGROUND: Plasma-cell neoplasms of the head and neck include extramedullary plasmacytoma and solitary plasmocytoma of bone or may represent a local manifestation of multiple myeloma. Involvement of sphenoid sinus has been rarely reported in multiple myeloma. METHODS: We present the case of a 77-year-old man with a 3-year-history of benign monoclonal IgG-lambda gammopathy who developed left sixth-nerve palsy and malaise. RESULTS: Computed tomography scan and magnetic resonance imaging scan disclosed a large soft-tissue mass of the sphenoid sinus with bone destruction. Sphenoid sinus biopsy revealed an IgG monoclonal plasma cell neoplasm. Diagnosis of multiple myeloma stage IA was then established. CONCLUSIONS: Diagnosis of plasma-cell neoplasm should be considered in sphenoid sinus tumors and depends upon histologic examination. This case enlightens the relationships between monoclonal benign gammopathy and plasma-cell neoplasms of the head and neck which constitute a continuum of B-cell lymphoproliferative disorders.
BACKGROUND: Plasma-cell neoplasms of the head and neck include extramedullary plasmacytoma and solitary plasmocytoma of bone or may represent a local manifestation of multiple myeloma. Involvement of sphenoid sinus has been rarely reported in multiple myeloma. METHODS: We present the case of a 77-year-old man with a 3-year-history of benign monoclonal IgG-lambda gammopathy who developed left sixth-nerve palsy and malaise. RESULTS: Computed tomography scan and magnetic resonance imaging scan disclosed a large soft-tissue mass of the sphenoid sinus with bone destruction. Sphenoid sinus biopsy revealed an IgG monoclonal plasma cell neoplasm. Diagnosis of multiple myeloma stage IA was then established. CONCLUSIONS: Diagnosis of plasma-cell neoplasm should be considered in sphenoid sinus tumors and depends upon histologic examination. This case enlightens the relationships between monoclonal benign gammopathy and plasma-cell neoplasms of the head and neck which constitute a continuum of B-cell lymphoproliferative disorders.