Thyroid adenolipomas or thyrolipomas are rare benign neoplasms composed of mature adipose tissue and glandular elements. The most common clinical manifestation is a slowly enlarging neck mass. If thyroid fine-needle aspiration biopsy discloses a mixed population of adipocytes and follicular cells, the possibility of an adenolipoma should be considered in the differential diagnosis. Complete surgical excision is curative and the prognosis is favorable. We report a case of a 61 year-old female, with a recent diagnosis of multinodular goitre. The diagnosis of adenolipoma was only possible after surgery, performed because of a suspicious fine-needle aspiration biopsy. We also briefly discuss the pathogenesis, clinic and diagnosis of this entity.