Primary plasmacytoma of the thyroid gland: a case report of a rare neoplasia

extramedullary plasmacytoma comprises 3%-5% of all plasma cell neoplasms, and approximately 80% of the cases occur in the upper respiratory tract. primary thyroid plasmacytomas (ptp) are rare tumors. the authors report a case of ptp in a male patient with dyspnea and dysphagia. physical examination and computerized tomography (ct) scan revealed a solid tumor affecting the thyroid gland, measuring 12 cm in its greatest dimension. surgical biopsy was performed. microscopy revealed a hypercellular malignant neoplasm composed of round plasmacytoid cells arranged in solid nests, which showed a positive immunoexpression for cd138, epithelial membrane antigen (ame), kappa light chains and multiple myeloma oncogene 1 (mum1). the diagnosis of ptp was accordingly established.