Expect the Unexpected: Report of a Case of Pediatric Pharyngeal Extraosseous Plasmacytoma with Tumefactive Amyloidosis ('Amyloidoma') and a Review of the Literature

We report a rare case of localized pharyngeal tumefactive amyloidosis caused by extraosseous plasmacytoma in a 12 year-old girl who presented with otalgia, sore throat and blood stained sputum. The tumor was predominantly composed of amyloid with a limited component of well-differentiated neoplastic plasma cells, which were monoclonal (kappa restricted) on light chain in-situ hybridization. The amyloid deposits were positive for kappa immunoglobulin light chain on immunohistochemistry. The patient was treated with a combination of surgery and radiotherapy. Follow-up at 1 year showed no evidence of recurrence or progression.