Multifocal ectopic thyroid tissues including breast: A case report

Abstract

The current study reports the case of multifocal ectopic thyroid tissues in the breast. Ectopic thyroid tissue is an uncommon entity found not only in the cysts of thyroglossal ducts, but also along the thyroglossal duct. The most frequent location of this tissue is the base of the tongue, but they can also occur in the anterior tongue, submandibular or sublingual region, larynx, trachea, mediastinum and heart. Only a single case of ectopic thyroid tissue in breast has been previously reported in English literature. However, the current case was associated with abnormal embryological development compared with previous reports, which are attributed to abnormal implantation.

Keywords: ectopic thyroid tissue.

Figure 1.

(A) The mammography and (B) ultrasonography of patient shows multiple well demarcated nodules in left breast (arrows). Radiologist reported this lesion as Breast Imaging-Reporting and Data System 2.

Figure 2.

(A) The hematoxylin and eosin stain slide of received core biopsied tissue shows thyroid follicles in fatty tissue. (B) These follicular cells are strongly positive for thyroid transcription factor-1 immunohistochemistry staining and consistent with thyroid follicles. (C) On higher magnification, there are some normal mammary ducts and (D) they indicated estrogen receptor expression.