Plasma Cell Lesions of the Thyroid: Report of a Case of Solitary Plasmacytoma and a Review of the Literature

Abstract

We report a case of a solitary plasmacytoma arising from a thyroid with longstanding Hashimoto's disease, and diagnosed by fine-needle aspiration cytology. Serum protein electrophoresis revealed an M-spike in the gamma-globulin region due to monoclonal IgG-lambda immunoglobulin. The thyroid tumor was treated with near-total thyroidectomy and irradiation, and the patient was well 6 years after surgery without evidence of multiple myeloma. The serum M-spike disappeared after the tumor resection and radiation therapy. Plasma cell lesions of the thyroid reported in the world literature are extensively reviewed. Solitary plasmacytomas occur most commonly in patients with Hashimoto's disease, and must be distinguished from plasma cell granulomas and involvement of the thyroid in multiple myeloma. Plasmacytomas should be considered in the differential diagnosis of a rapidly enlarging thyroid mass in a patient with known Hashimoto's disease.

Malignant Lymphoma of the Thyroid: A 30-Year Clinicopathologic Experience and an Evaluation of the Presence of Epstein-Barr Virus

“…More than 60 cases were documented in the English literature. 21 The plasmacytomas were slightly more common in women (male/female ratio, 1:1.3). The mean age at initial examination was 62 years (range, 32 to 87 years).…”

Cytological Findings for the Diagnosis of Primary Thyroid Mucosa-Associated Lymphoid Tissue Lymphoma by Fine Needle Aspiration

“…FNAC of thyroid primary malignant lymphoma is useful as a preoperative qualitative diagnostic procedure, and previous studies have attempted to improve the diagnostic accuracy of FNAC [6,7,8,9,10,11,12,13,14,15,16,17,18,19,22,23,24,25,26,27,28,29,30,31]. However, some of those studies [8,9,10,11,12,17,22,23,24,25,26,27,29,30] did not include any cases of MALT lymphoma, while those that did [7,13,14,15,16,17,18,19,28,31] only examined a few cases.…”

“…However, some of those studies [8,9,10,11,12,17,22,23,24,25,26,27,29,30] did not include any cases of MALT lymphoma, while those that did [7,13,14,15,16,17,18,19,28,31] only examined a few cases. For this reason, we considered the present conditions for cellular analysis based on the concept of MALT lymphoma to be insufficiently accurate.…”

“…However, the diagnosis of lymphoma has been considered more appropriate than plasmacytoma when lymphocytes and PC in the lesion are CD20 positive [3]. Among cytological studies [7,19,22,23,24,25,26,27,28,29,30,31] regarding plasmacytoma or MALT-EPCD of the thyroid gland, prior to the publication of the WHO classification in 2001, immunohistochemical classification is discussed in only 1 article [27], and there are only few studies [7,19,28,29,30,31] on cytology based on the WHO classification [2,3]. Therefore, more data should be collected to discriminate MALT-EPCD from extramedullary plasmacytoma.…”

Thyroid low‐grade B‐cell lymphoma (MALT type) with extreme plasmacytic differentiation: Report of a case diagnosed by fine‐needle aspiration and flow cytometric study

“…Some cases may complicate Hashimoto's thyroiditis. 20 EMP is composed of a monomorphous population of plasma cells instead of a mixed population of lymphocytes, plasma cells, and lymphoplasmacytoid cells seen in MALT lymphoma. It has been suggested that cases previously reported as EMP of the thyroid represent MALT lymphoma with extreme plasma-cell differentiation 10,21 because the clinical behavior appears similar.…”