Endocrine Abstracts

Introduction

Extramedullary plasmacytoma (EMP) is a plasma cell neoplasm of extraosseous tissues. Less than 5% of all plasma cell neoplasms develop extramedullary. EMP is most common in the upper respiratory tract and oral cavity. The thyroid gland is one of the extremely rare regions. It is more common in men and the average age at diagnosis is 55. Primary thyroid plasmacytoma is one of the rare thyroid neoplasms. It often manifests as a rapidly growing mass in the neck and cause symptoms due to mass pressure. Pathological evaluation is particularly important. At the diagnosis of thyroid plasmacytoma, multiple myeloma must be ruled out. Here we present our case of thyroid plasmacytoma diagnosed by tru-cut biopsy.

Case

A 71-year-old female patient, with hypothyroidism and multinodular goiter since 2014, presented with a 6-month history of dyspnea and neck swelling. She had type 2 diabetes mellitus, hypertension, and coronary artery disease. Thyroid gland was grade 3, fixed nodules were bilateral palpable. Thyroid function tests were euthyroid on levothyroxine treatment and thyroid autoantibodies were positive. An ultrasound scan of the thyroid revealed an enlarged thyroid with thyroid nodules on the right and left lobes, extending to the isthmus with a significant increase in size compared to previous controls. Fine needle aspiration cytology was benign. Due to suspicion of thyroid lymphoma, tru-cut biopsy was performed which suggested plasma cell neoplasia and plasmacytoma. Hematology consultation was made, as a result of the tests, multiple myeloma and other plasma cell disorders were excluded. The patient was evaluated as extramedullary plasmacytoma. In the council of endocrinology and metabolism, hematology, general surgery, nuclear medicine and radiation oncology departments operation was preferred. Bilateral total thyroidectomy was performed, histopathology reported as plasma cell neoplasm. Radiotherapy was not considered to be given to the patient as she had no residue in the examinations performed in the postoperative period. The patient has been followed in remission for one year.

Conclusion

Primary thyroid plasmacytoma is a rare thyroid neoplasm. Clinical examination and imaging methods are usually not determinative in diagnosis, pathological evaluation is at the forefront of diagnosis. Even if fine needle aspiration biopsy is benign, patients should be evaluated for tru-cut biopsy in case of clinical suspicion. In the begining, multiple myeloma must be ruled out. Regular follow-up of the patient is necessary, as conversion to multiple myeloma may occur rarely.