A Case of Solitary Extramedullary Plasmacytoma of the Thyroid Presented as a Thyroid Tumor with Hashimoto's Thyroiditis

Abstract

Extramedullary plasmacytomas most commonly occur in the nasal cavity, nasopharynx, paranasal sinuses, and larynx. Solitary extramedullary plasmacytoma (SEP) of the thyroid gland is rare. The diagnosis of SEP of the thyroid by cytology is typically difficult before surgery, and the entity is often confused with different cytology findings. We report a case of a 59-year-old man with pri mary plasmacytoma of the thyroid presented as a rapidly enlarging thyroid gland with Hashimoto’s thyroiditis. He had been suffering from anterior neck swelling for 1 month. Several fine-needle aspiration biopsies yielded Hashimoto’s thyroiditis. During a follow-up period of 3 years, the size of the thyroid gland increased and a mass lesion in right thyroid gland was detected. A total thyroidectomy was performed based on a diagnosis of a thyroid tumor with Hashimoto’s thyroiditis. Permanent pathology identified the mass as an extramedullary plasmacytoma associated with Hashimoto’s thyroiditis. Skeletal survey and serum electropho resis tests were normal, and a bone marrow biopsy yielded no evidence of multiple myeloma. The patient underwent definitive ra diotherapy and remained free from any recurrences during follow-up. (Endocrinol Metab 27:77-82, 2012)