BACKGROUND: Diffuse lipomatosis of the thyroid gland is a particularly rare histopathological condition characterized by diffuse fatty infiltration within the thyroid stroma.

CASE REPORT: We report a case of a 53-year-old woman who presented with a 2-year history of massive neck goiter and mild dysphagia. A computed tomography (CT) scan revealed heterogeneous enhancing of an enlarged thyroid gland with left lobe cranial extension and compression of the pharynx, and caudal bilateral retrosternal growth. The patient underwent total thyroidectomy and histopathological examination revealed mature fatty tissue diffusely distributed throughout the thyroid gland. Excision of the gland was somewhat challenging due to the very thin thyroid capsule and recurrent protrusion of fat from the capsule.

CONCLUSIONS: Diffuse thyroid lipomatosis is an extremely rare histopathological condition characterized by diffuse fatty infiltration in thyroid stroma. Despite its rarity, it should be considered in the differential diagnoses of a patient presenting with a goiter.

Keywords: Goiter, Lipomatosis, Thyroid Diseases