Extramedullary plasmacytoma of the thyroid, associated with follicular colonization and stromal deposition of polytypic immunoglobulins and major histocompatibility antigens. Possible categorization in MALT lymphoma

A Case Report of Thyroid Plasmacytoma and Literature Update

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.

Extramedullary plasmacytoma of thyroid - a mimicker of medullary carcinoma at fine needle aspiration cytology: A case report

A rare case of extra medullary plasmacytoma (EMP) of thyroid gland in a 60 year old male, occurring against a background of Hashimoto's thyroiditis is reported. The fine needle aspiration cytology (FNAC) initially done as an outpatient procedure, showed atypical epithelial cells on a background of amyloid. Considering these findings we gave a diagnosis of medullary carcinoma. Histology of the total thyroidectomy specimen showed an extensive infiltration of neoplastic plasma cells against a background of Hashimoto's thyroiditis, with a bizarre Hurthle cell change. Immunohistochemistry on the histology sections confirmed the diagnosis of solitary plasmacytoma of thyroid against a background of Hashimoto's thyroiditis.

PAS-positive extracellular deposits within germinal centers of hyperplastic follicles during SIV infection in a rhesus macaque

BACKGROUND

Lymphoid tissue remodeling is characteristic of chronic simian immunodeficiency virus infection.

METHODS

A rhesus macaque infected with SIVmac239 was necropsied and its lymphoid tissues subjected to histopathology characterization.

RESULTS

Germinal centers in spleen and lymph nodes contained PAS-positive, non-amyloid extracellular deposits, decreased T follicular helper cells, and normal density of Ki67(+) B cells.

CONCLUSIONS

A possible mechanism for PAS-positive deposits includes exaggerated involution of SIV-induced follicular hyperplasia secondary to virus-associated immune reaction.