Abstract
Plasmacytomas of the thyroid gland are rare, whether or not they arise as solitary (primary) lesions or secondary to systemic multiple myeloma. Here, we present the case of a 71-year-old female presenting with goiter and Hashimoto's thyroiditis, in whom the subsequent histopathological diagnosis of plasmacytoma was a surprise. In presenting this case, we summarize the last 25 years of literature on thyroid plasmacytoma and review the salient clinicopathological characteristics, differential diagnoses, management, and outcomes of this rare condition.