Plasma cell granuloma of the thyroid gland mimicking carcinoma: a case report and review of the literature

Plasma cell granulomas (PCG) are rare tumor-like lesions consisting of sheets of polyclonal plasma cells admixed with numerous lymphocytes and other inflammatory cells surrounded by fibrous stroma. They usually appear in the lung, but involvement of diverse extrapulmonal sites has been described. PCGs occurring in the thyroid are very uncommon. Since 1981, only 11 cases have been described in the English literature. Here, we present the case of a 50-year-old Arabic man who noticed an enlargement of his thyroid gland during the previous 2 years, and he developed swallowing disturbances and a feeling of narrowness in the neck. A nearly total resection of the thyroid gland was made because of clinical suspicion of carcinoma. On histologic examination, PCG of the thyroid associated with Hashimoto's thyroiditis (HT) was diagnosed. This is the first case in which molecular pathological analyses for EBV and HHV8 DNA were made. As these were negative, distinct etiological features were suggested.