Thyroid lesions containing mature adipose tissue: 7 case reports

Lesions characterized by mature adipose tissue in thyroid gland are thyrolipoma, described as a capsulated benign nodule and thyrolipomatosis, diffuse infi ltration of adipose tissue in parenchyma. Here, we present 4 thyrolipoma and 3 thyrolipomatosis cases. All cases were female with ages from 42 to 67. The median age was 56 years. Five cases presented neck mass, 1 with angerness and tremor and 1 with anemia and hypercalsemia. All cases revealed multinodular goiter in physical examination confi rmed ultrasonographically and went on fi ne needle aspiration (FNA) biopsy. Five of the FNA biopsies were diagnosed as benign and 2 cases as suspected for follicular neoplasm. Six cases operated bilaterally whereas 1 case had right lobectomy. The surgical specimens showed multiple colloidal nodules, some of which were described as implying yellow gray areas. Histologically, 4 cases had nodules with fat tissue, diagnosed as thyrolipoma. Three cases demonstrated scattered adipocytes in parenchyma known as thyrolipomatosis. Additionally, in one case fat tissue containing papillary carcinoma and in another case papillary microcarcinoma were observed. The patients had no recurrence after surgery and one case we went onradioactive iodine therapy. It is important to be aware of these lesions for preventing pathologists from misdiagnosis especially in frozen sections and cytologic materials.