An Enlarged Goiter Presenting with a Rare Diffuse Lipomatosis of the Thyroid Gland

Abstract

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.

Figure 1.

(A) A coronal CT with contrast showing heterogeneous enhanced thyroid with cystic changes and a heterogeneous enhanced thyroid mass lesion. The thyroid gland extends up to the pharynx and down to the sternum (arrows). (B) An axial CT with contrast showing heterogeneous thyroid with a heterogeneous enhanced mass lesion. The thyroid extends up and posteriorly reaching the right pyriform fossa, exerting compression on the oropharynx and extending down the retrosternal (arrow). The tracheal air column in the neck is patent and displaced to the left side.

Figure 2.

(A) Microscopic examination at low magnification showing admixture of adipocytes (arrows) with follicular thyroid cells (hematoxylin and eosin stain). (B) Microscopic examination at higher magnification of adipocytes (arrows).