A postmenopausal woman with gross cystic disease fluid protein-15 and estrogen receptor-positive recurrence of papillary thyroid cancer.

BACKGROUND

The presence of estrogen receptors (ERs) in both normal and neoplastic thyroid tissues has been demonstrated in numerous publications. Growth-stimulatory effects of estrogen on thyroid tissue have been postulated to account for the prevalence of thyroid cancers in premenopausal women. However, the role of ERs in mediating these effects is by no means clear-cut, and the significance of ER expression by thyroid carcinomas is currently unknown. This article reports a patient with papillary thyroid cancer and a rare profile of immunohistochemical markers.

SUMMARY

A 67-year-old woman underwent a total thyroidectomy for papillary thyroid carcinoma and received radioiodine therapy postoperatively. The patient presented 3 months postoperatively with an enlarging neck mass at the surgical site associated with compressive symptoms and vocal cord paralysis. The patient underwent modified radical neck dissection for debulking of the recurrent tumor, which was invading into the prevertebral fascia. Immunohistochemical analysis of the resected mass revealed positive staining for ER-alpha (ER-alpha) and for gross cystic disease fluid protein 15, both markers with specificities for mammary carcinomas. However, evaluation for a possible primary breast cancer was negative. This case represents an unusual presentation of a rapidly recurring papillary thyroid carcinoma masquerading immunohistochemically as a primary breast cancer. Although the existence of ER-positive thyroid cancer has been well established, the dramatic increase in ER expression between initial and recurrent tumors in this postmenopausal woman raises the question of the significance of these receptors to the progression of the disease. Further, this case is the first to our knowledge to document gross cystic disease fluid protein 15 expression by a primary thyroid carcinoma.

CONCLUSIONS

This case highlights the need to further explore the possible ramifications of ER expression in thyroid malignancy.