Introduction. We present a case of an 89-year-old female who attended our surgical endocrine clinic with a 3-month history of a left-sided neck lump. There was no past medical history of thyroid disease. Methods. Following examination and further investigation, including core biopsy, a diagnosis of plasma cell granuloma of the thyroid was made. Biochemical testing of thyroid function and Thyroid Peroxidase Antibody was in-keeping with an associated Hashimoto's thyroiditis. Results. The patient was treated conservatively with thyroxine and regularly seen in clinic. TSH levels improved and the lump showed signs of regression. Conclusion. Plasma cell granuloma of the thyroid is rare with only 16 previously reported cases. We present a new approach to management without the use of surgery or steroids. The literature is reviewed comparing clinico-pathological features and management of other reported cases.