Ectopic thyroid presenting as a gallbladder mass

Abstract

The ectopic thyroid tissue is the result of abnormality in embryological development and migration. Ectopic thyroid tissue located in or adjacent to the gallbladder wall is extremely rare with only two cases reported since 1969. These cases were all identified incidentally by pathological examination after cholecystectomy for acute or chronic cholecystitis. We here report a case of ectopic thyroid tissue presenting as a gallbladder mass in a 60-year-old woman who underwent cholecystectomy. Ectopic thyroid tissue in the gallbladder wall was confirmed by histopathology.

Figure 1

(A) Histological examination revealed well-differentiated ectopic thyroid follicles in the subserosal layer of the gallbladder wall (H&E, × 100), which showed no morphological features of cellular atypia including nuclear grooving, nuclear cytoplasmic inclusions and psammoma bodies. (B) Immunohistochemical examination showed positive immunoreactivity of thyroglobulin (TG) of the ectopic thyroid tissue specimen (×100).

Figure 2

(A) Photograph of the resected gallbladder showing a cystic mass under the serosal layer of the gallbladder wall. (B) Ultrasonography showed no stones in the gallbladder but a focal thickened wall. (C) CT scan showed a mass lesion (43Hu) in the body of the gallbladder wall approximately 1.9 × 1.7 × 1.1 cm (axial). (D) Contrast-enhanced CT scan showed no obvious enhancement of the mass in the gallbladder wall (coronal axes).