Thyroid Hemiagenesis and Ectopic Thymus at Thyroid Bed, and Papillary Cancer in Opposite Thyroid Lobe with Hyperthyroidism

ABSTRACT

Thyroid hemiagenesis is a development failure of one of the thyroid lobes, predominantly in females with a left lobe. The associated disease in the remaining thyroid lobe include benign adenoma, multinodular goiter, hyperthyroidism, chronic thyroiditis, and carcinoma etc. We report a very rare case of thyroid hemiagesesis with hyperthyroidism, thyroid cancer, and ectopic thymus. A 43-year-old female presented with hyperthyoidism and thyroid nodule. Thyroid scan with 99mTcO4 revealed cold nodule in left lobe with absent right lobe. The patient underwent thyroid exploration. Because nodule in the remaining thyroid lobe proved to be a thyroid cancer on frozen biopsy, total thyroidectomy was performed. There was a thyroid-like tissue at the right side (scan 'absent' side) and removed. Pathology confirmed that the removed tissue from right side was thymus. There has been no report in world literatures of such case; in one patient, thyroid hemiagenesis, hyperthyroidism, thyroid carcinoma, and ectopic thymus coexists. We report the case and review the literature on thyroid hemiagenesis and ectopic thymus.