Eur J Anat, 12 (2): 127-132 (2008)

Agenesis of isthmus of thyroid gland and ectopic locations of the inferior parathyroid glands and thymus

Kalpana R., Madhavi C., Apurva S.

Department of Anatomy, Christian Medical College, Vellore-632002 Tamil Nadu, India; Department of Pathology, Christian Medical College and Hospital, Vellore-632004, India

ABSTRACT The aim of this study is to report a case of agenesis of the isthmus of the thyroid gland, and ectopic locations of the inferior parathyroid glands and thymus observed in an 80-year old female cadaver during routine dissection of the head and neck. The two lobes of the thyroid gland were small and connected by pretracheal fascia at the midline, which upon histological study were seen to contain mainly connective tissue, with a few minute follicles laterally. A 2.5-cm-long portion of glandular tissue was seen posterior to the left lobe, which upon histological study proved to be an ectopic thymus with cysts. The location of the superior parathyroid glands was normal. The right inferior parathyroid gland was situated close and anteriorly to the inferior pole of the right lobe. The left inferior parathyroid gland was seen within the thymus in the superior mediastinum. Ectopic locations of the inferior parathyroid gland and the thymus have been attributed to abnormal migration during embryogenesis and common origin from the third pouch.

Keywords: aged, anatomical variation, article, cadaver, case report, ectopic organ, ectopic thymus, female, histopathology, human, human tissue, mediastinum, neck dissection, parathyroid ectopia, thyroid dysgenesis, thyroid follicle